Send volume just once when starting the stream.

The volume is in the Start command already, no need to send it in a
separate command.

Bug: 116317072
Bug: 116044083
Bug: 116145308
Test: play music, pause, adjust volume, start playing again, verify
      playing was re-started with proper volume level.
Change-Id: I2a900b03a35670de4a265184f333517db17497d8
Merged-In: I76f4b6a9302dd84781195475de50374e9c30700f