Adds a sentence about Compute API v2 and v3 XML deprecation

- for requests and responses in the Compute APIs

Also, use clouddocs-maven-plugin 2.1.2.

Change-Id: I1cd2e04e4634180141e67c277a6d9607ecfb23d9
Partial-Bug:1283341

api-ref/src/docbkx/ch_compute-v2-ext.xml

@@ -14,6 +14,8 @@
     <para>Extensions add features, MIME types, actions, states,
         headers, parameters, and resources to the core Compute API
         without requiring a version change.</para>
+    <note><para>XML support in requests and responses has been
+        deprecated for the Compute API v2.</para></note>
     <section xml:id="ext-action">
         <title>Server admin actions (action)</title>
         <para>Administrator only. Perform actions on a server. Specify

api-ref/src/docbkx/ch_compute-v2.xml

@@ -10,6 +10,8 @@
     <title>Compute API v2 (CURRENT)</title>
     <para>Launch virtual machines from images or images stored on
         persistent volumes. API v1.1 is identical to API v2.</para>
+    <note><para>XML support in requests and responses has been
+        deprecated for the Compute API v2.</para></note>
     <section xml:id="compute_versions">
         <title>API versions</title>
         <para>List information for all API versions and show details

api-ref/src/docbkx/ch_compute-v3.xml

@@ -12,6 +12,8 @@
   version="5.0-extension RackBook-2.0" xml:id="compute-ext-v3"
   role="api-reference">
   <title>Compute API v3 (EXPERIMENTAL)</title>
+  <note><para>XML support in requests and responses has been
+    deprecated for the Compute API v3.</para></note>
   <!-- GET v3/extensions does not work -->
   <!-- <para>Query the Compute API to list available extensions with a
     &GET; request to <code>v3/extensions</code>.</para>-->

pom.xml

@@ -39,7 +39,7 @@
       <plugin>
         <groupId>com.rackspace.cloud.api</groupId>
         <artifactId>clouddocs-maven-plugin</artifactId>
-        <version>2.1.1</version>
+        <version>2.1.2</version>
       </plugin>
     </plugins>
   </build>