libstagefright: support for disabling buffer metadata (kitkat style)

 - Metada mode video recording is enabled by default.
 - use setprop debug.camcorder.disablemeta 1 to disable metadata mode recording.

 kitkat style:
 - Move disablemeta to checkVideoEncoderCapabilities()
 - don't query hardware codecs

(cherry picked from commit 6e858df631c4347989ac093bec64bc757e86d76f)
Change-Id: I7208af27c8149770f5f841e016ee1ce7cbd19dc2