HeadsUp: Only remove heads up if attached to window

Attempting to remove mHeadsUpNoficiationView from the window manager
when it is not currently attached will throw an IllegalArgumentException
so we check if it is attached and if so remove it, otherwise carry on.

Change-Id: Ida916eba496c4183e47288ef24a8a93c46a7eddf

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java
Revert "Merge Derp"

This reverts commit 6f1328419a73864e36c2c34119d1f0858e289d5b.
Revert "Use actual storage type of sdcard/usb (1/2)."

This reverts commit 77c035b07f3433c994333a7a1c9719cb4084c2d0.