stagefright: Revert patches which should not have carried over

 * These patches cause problems on L, revert them.

Revert "Disconnect the mediaplayer when reset"

This reverts commit 9ab0b00d.

Revert "Remove potential cause of underrun."

This reverts commit a6027112.

Change-Id: I1ee0a447cc5820afd4c068170d6d04b50e45a36d