Reset the audio stream volume to fix low in-call volume bug

Due to a bug in the OMX system, the audio stream volume is set to 0
after it was set to it's default volume.
Calling PhoneUtils.resetAudioStreamVolume() triggers the system to
reset the volume.
This should be called on every place where is switched between
audio modes.
REMARK: I think it only appears on the voice call stream,
        but to be sure I also do it on the bluetooth stream.

Change-Id: Ie08f9dcd1814eb923a43ac7935935577a38b0571