audio policy: apply default device volume

Make sure that we apply default device volume to
active outputs in case no specific volume for selected
device is received afterward.

Bug: 9760269.
Change-Id: I216de40396e1075e77493c97e8b192cd3a31d546
Merge tag 'android-4.3.1_r1' into jb43

Android 4.3.1 Release 1

Conflicts:
	audio/AudioPolicyManagerBase.cpp