Disable 10secs forward/backward seeking for rtsp as seek is a very expensive operation there. Decouple the 10sec forward/backward button functionality from seekbar functionality.

Change-Id: I016e79b688774f8ee91ac53216197b5fb9cb41b2
related-to-bug: 3073955
diff --git a/include/media/Metadata.h b/include/media/Metadata.h
index 241868a..9c915ce 100644
--- a/include/media/Metadata.h
+++ b/include/media/Metadata.h
@@ -91,6 +91,7 @@
     static const Type kPauseAvailable = 29;        // Boolean
     static const Type kSeekBackwardAvailable = 30; // Boolean
     static const Type kSeekForwardAvailable = 31;  // Boolean
+    static const Type kSeekAvailable = 32;         // Boolean
 
     // @param p[inout] The parcel to append the metadata records
     // to. The global metadata header should have been set already.