Revert "Translucent volume panel"

This reverts commit aa6d288e6d78bfedce51c37c334caad563f332ac.
Test: VolumePanel: Rework design on top of Hover

Signed-off-by: David L.-W. <xD_e-mail@gmx.de>

Conflicts:
	core/java/android/view/VolumePanel.java