Fix build for gcc 4.6.4.

Change-Id: I59457bf90cf2f457cbbad70ae524af76ed1e89a4
(cherry picked from commit 6498b799)

avmedia/source/gstreamer/gstplayer.cxx

@@ -90,7 +90,7 @@ private:
 };
 
 class MissingPluginInstaller {
-    friend MissingPluginInstallerThread;
+    friend class MissingPluginInstallerThread;
 
 public:
     MissingPluginInstaller(): launchNewThread_(true), inCleanUp_(false) {}