ignore invlaid play position update from remote control client.

differentiate between applications that use
 the new RemoteControlClient APIs to pass a playback position but
 don't have one yet, and applications that use the legacy API and
 will never pass a position.

bug:9294855
Change-Id: I015b9ded72497464352a9fbb6a605cedfffad373
Merge "ignore invlaid play position update from remote control client." into jb-mr2-dev
Merge tag 'android-4.3.1_r1' into jb431

Android 4.3.1 Release 1

# gpg: Signature made Mon 07 Oct 2013 01:39:30 PM CDT using DSA key ID 9AB10E78
# gpg: Can't check signature: No public key