Fix "superceded" typo in schema

Clouds are hard.  English, doubly so.  We have a longstanding
spelling error in the schema: "superceded" should be spelled
"superseded".  This patch corrects it and updates all the documents
the typo was propagated to over time.

Change-Id: I72f24bf026919f4ccce0ce0c42e1c33c4042aca4

2015.03.json

@@ -2,7 +2,7 @@
   "id": "2015.03",
   "schema": "1.2",
   "source": "http://git.openstack.org/cgit/openstack/defcore/",
-  "status": "superceded",
+  "status": "superseded",
   "replaces": "2014.07",
   "releases": ["havana", "icehouse"],
   "platform": {

2015.04.json

@@ -2,7 +2,7 @@
   "id": "2015.04",
   "schema": "1.2",
   "source": "http://git.openstack.org/cgit/openstack/defcore/",
-  "status": "superceded",
+  "status": "superseded",
   "replaces": "2015.03",
   "releases": ["havana", "icehouse", "juno"],
   "platform": {

2015.04/procedure.rst

@@ -4,6 +4,6 @@ Kilo Cycle DefCore Testing for Vancouver Summit.
 Testing against Defcore 2015.04 Capabilities
 --------------------------------------------
 
-The 2015.04 guideline is now superceded and
+The 2015.04 guideline is now superseded and
 can no longer be used to qualify for the
 OpenStack Powered Trademark program.

2015.05.json

@@ -2,7 +2,7 @@
   "id": "2015.05",
   "schema": "1.2",
   "source": "http://git.openstack.org/cgit/openstack/defcore/",
-  "status": "superceded",
+  "status": "superseded",
   "replaces": "2015.04",
   "releases": ["icehouse", "juno", "kilo"],
   "platform": {

2015.05/procedure.rst

@@ -4,7 +4,7 @@
 Testing against Defcore 2015.05 Capabilities
 --------------------------------------------
 
-The 2015.05 guideline is now superceded and
+The 2015.05 guideline is now superseded and
 can no longer be used to qualify for the
 OpenStack Powered Trademark program.
 

2015.07.json

@@ -3,7 +3,7 @@
   "schema": "1.5",
   "reference": "https://git.openstack.org/cgit/openstack/defcore/schema/1.5.json",
   "source": "http://git.openstack.org/cgit/openstack/defcore/",
-  "status": "superceded",
+  "status": "superseded",
   "replaces": "2015.05",
   "target_approval": "2015-07-28",
   "releases": ["icehouse", "juno", "kilo"],

2016.01.json

@@ -3,7 +3,7 @@
   "schema": "1.5",
   "reference": "https://git.openstack.org/cgit/openstack/defcore/schema/1.5.json",
   "source": "http://git.openstack.org/cgit/openstack/defcore/",
-  "status": "superceded",
+  "status": "superseded",
   "cutoff_score": "74",
   "target_approval": "2016-01-27",
   "replaces": "2015.07",

2016.08.json

@@ -3,7 +3,7 @@
   "schema": "1.6",
   "reference": "https://git.openstack.org/cgit/openstack/defcore/schema/1.6.json",
   "source": "http://git.openstack.org/cgit/openstack/defcore/",
-  "status": "superceded",
+  "status": "superseded",
   "cutoff_score": "74",
   "target_approval": "2016-08-23",
   "replaces": "2016.01",

doc/source/guidelines/2015.03.rst

@@ -2,7 +2,7 @@
 OpenStack DefCore 2015.03
 =========================
 
-:Status: superceded
+:Status: superseded
 :Replaces: 2014.07
 :JSON Master: http://git.openstack.org/cgit/openstack/defcore/tree/2015.03.json
 

doc/source/guidelines/2015.04.rst

@@ -2,7 +2,7 @@
 OpenStack DefCore 2015.04
 =========================
 
-:Status: superceded
+:Status: superseded
 :Replaces: 2015.03
 :JSON Master: http://git.openstack.org/cgit/openstack/defcore/tree/2015.04.json
 

doc/source/guidelines/2015.05.rst

@@ -2,7 +2,7 @@
 OpenStack DefCore 2015.05
 =========================
 
-:Status: superceded
+:Status: superseded
 :Replaces: 2015.04
 :JSON Master: http://git.openstack.org/cgit/openstack/defcore/tree/2015.05.json
 

doc/source/guidelines/2015.07.rst

@@ -2,7 +2,7 @@
 OpenStack DefCore 2015.07
 =========================
 
-:Status: superceded
+:Status: superseded
 :Replaces: 2015.05
 :JSON Master: http://git.openstack.org/cgit/openstack/defcore/tree/2015.07.json
 

doc/source/guidelines/2016.01.rst

@@ -2,7 +2,7 @@
 OpenStack DefCore 2016.01
 =========================
 
-:Status: superceded
+:Status: superseded
 :Replaces: 2015.07
 :JSON Master: http://git.openstack.org/cgit/openstack/defcore/tree/2016.01.json
 

doc/source/guidelines/2016.08.rst

@@ -2,7 +2,7 @@
 OpenStack Interoperability Guideline 2016.08
 ============================================
 
-:Status: superceded
+:Status: superseded
 :Replaces: 2016.01
 :JSON Master: http://git.openstack.org/cgit/openstack/interop/tree/2016.08.json
 

doc/source/schema/1.5.json

@@ -31,7 +31,7 @@
       "type": "string"
     },
     "status": {
-      "enum": [ "draft", "advisory", "approved", "superceded" ]
+      "enum": [ "draft", "advisory", "approved", "superseded" ]
     },
     "replaces": {
       "type": "string"

doc/source/schema/1.6.json

@@ -31,7 +31,7 @@
       "type": "string"
     },
     "status": {
-      "enum": [ "draft", "advisory", "approved", "superceded" ]
+      "enum": [ "draft", "advisory", "approved", "superseded" ]
     },
     "replaces": {
       "type": "string"

doc/source/schema/2.0.json

@@ -70,7 +70,7 @@
               "uniqueItems": true
             },
             "status": {
-              "enum": ["draft", "advisory", "approved", "superceded"]
+              "enum": ["draft", "advisory", "approved", "superseded"]
             }
           },
           "required": [