Revert "Issue #21 - Remove TelemertyVFS"

This:
- reverts commit 83ecae9ff7ee1469da1675435dbcf26d094aa1c6
- adds a failure check to Connection::GetQuotaObjects

This resolves #1768.

storage/mozStorageService.h

@@ -19,6 +19,7 @@
 
 class nsIMemoryReporter;
 class nsIXPConnect;
+struct sqlite3_vfs;
 
 namespace mozilla {
 namespace storage {
@@ -135,6 +136,8 @@ private:
    * synchronizing access to mLocaleCollation.
    */
   Mutex mMutex;
+  
+  sqlite3_vfs *mSqliteVFS;
 
   /**
    * Protects mConnections.