Bug 1316757, part 1 - Remove state machine user syntax from non-test IPDL files. r=billm

The state information in PWebBrowserPersistDocument.ipdl looks like
good documentation, so I only commented it out. The other one is
trivial so I deleted it.

MozReview-Commit-ID: C5SQAOPMnNB

--HG--
extra : rebase_source : 0ec19729458838b071156398bf3d1fb908cc6fe4

dom/plugins/ipc/PPluginBackgroundDestroyer.ipdl

@@ -28,9 +28,6 @@ protocol PPluginBackgroundDestroyer {
 
 parent:
     async __delete__();
-
-state DESTROYING:
-    recv __delete__;
 };
 
 }  // namespace plugins

embedding/components/webbrowserpersist/PWebBrowserPersistDocument.ipdl

@@ -73,6 +73,7 @@ child:
                                     uint32_t aWrapColumn);
   async __delete__();
 
+/*
 state START:
   recv Attributes goto MAIN;
   recv InitFailure goto FAILED;
@@ -85,6 +86,7 @@ state MAIN:
 
 state FAILED:
   send __delete__;
+*/
 };
 
 } // namespace mozilla