base

Volume: Ensure ring/notif slider is enabled when ringer=vibrate.

Although the audio policy makes a distinction between voice capable
and not when determining the default active stream, have the panel
recognize this condition and behave the same way (enable the slider)
on all devices.

Bug: 17405530
Change-Id: If3e1af3078f47bc1205545e919ccc6206020e7b2