Add pushBlankOnStop fix.

Fix wrong sidebandStream for push-blank-on-stop function.
We should set sidebandStream to nullptr before pushing blank buffer,
because blank buffer doesn't run in tunnel mode.

Test: MMP playback OK
Bug: 287924345
Change-Id: Iebbd11473a1accd2cb1ed71aaebc5a373482210c
1 file changed