Settings: add back button in actionbar on Status settings

for more consistence. We add it as drawable due that we still have 3 other
places in settings where it is missing.

We will change later....after that we should have worked every inconsistence out.

Change-Id: If21d03b04d2356fa78349baa8ff2fb3b008dacbf

Conflicts:
	src/com/android/settings/deviceinfo/Status.java