Revert "msm8960: Add shell property to use AwesomePlayer as default."

This reverts commit c463a3f88b7e4a5819a06998478b0e9ebf9c80a5.

It breaks a2dp playback from Music/Play Music apps.

Change-Id: Icb74c2d383af78a0afb00b184b1476c5d15d2633