Add functional test for task samples

It would be nice if there is a functional test to confirm
all the task samples are good for out-of-box testing. So
here we go.

Also Fix nova/boot-lock-unlock-and-delete scenario flavor,
nova/boot-and-associate-floating-ip flavor, nova/boot-and-rebuild.
Change flavor value from apsent on gate to regexp.

Change-Id: I033135828b960da4cc3fd35b96ee69f700815a35
Co-Authored-By: Roman Vasilets <rvasilets@mirantis.com>
Co-Authored-By: Fei Long Wang <flwang@catalyst.net.nz>

samples/tasks/scenarios/nova/boot-and-associate-floating-ip.json

@@ -11,7 +11,7 @@
           "name": "m1.tiny"
         },
         "image": {
-          "name": "cirros-0.3.2-x86_64-uec"
+          "name": "^cirros.*uec$"
         }
       },
       "context": {

samples/tasks/scenarios/nova/boot-and-associate-floating-ip.yaml

@@ -5,7 +5,7 @@
         flavor:
             name: "m1.tiny"
         image:
-            name: "cirros-0.3.2-x86_64-uec"
+            name: "^cirros.*uec$"
       runner:
         type: "constant"
         times: 1

samples/tasks/scenarios/nova/boot-and-rebuild.json

@@ -6,10 +6,10 @@
                     "name": "m1.tiny"
                 },
                 "from_image": {
-                    "name": "cirros-0.3.2-x86_64-uec"
+                    "name": "^cirros.*uec$"
                 },
                 "to_image": {
-                    "name": "cirros-0.3.2-x86_64-uec"
+                    "name": "^cirros.*uec$"
                 }
             },
             "runner": {

samples/tasks/scenarios/nova/boot-and-rebuild.yaml

@@ -4,9 +4,9 @@ NovaServers.boot_and_rebuild_server:
     flavor:
       name: "m1.tiny"
     from_image:
-      name: "cirros-0.3.2-x86_64-uec"
+      name: "^cirros.*uec$"
     to_image:
-      name: "cirros-0.3.2-x86_64-uec"
+      name: "^cirros.*uec$"
   runner:
     type: constant
     times: 5

samples/tasks/scenarios/nova/boot-lock-unlock-and-delete.json

@@ -6,7 +6,7 @@
                     "name": "m1.tiny"
                 },
                 "image": {
-                    "name": "cirros-0.3.2-x86_64-uec"
+                    "name": "^cirros.*uec$"
                 }
             },
             "runner": {

samples/tasks/scenarios/nova/boot-lock-unlock-and-delete.yaml

@@ -5,7 +5,7 @@
         flavor:
             name: "m1.tiny"
         image:
-            name: "cirros-0.3.2-x86_64-uec"
+            name: "^cirros.*uec$"
       runner:
         type: "constant"
         times: 10