Fix wrong activities coming to foreground when finishing others.

When finishing activities, sometimes activities from other task stacks
came to the foreground for a split second instead of the launcher.

I've not completely verified the root cause for that yet, but I assume
it happens because the former front-of-task activity is still part of
the mActivities list at the time setFrontOfTask is called (and thus
stays front-of-task), so when it's removed from the list later, there is
no activity in the list that has the front-of-task flag set.

This is a regression introduced by commit
fdf28cc4be5acab6e4a050b27742435dfe7ae0de, so revert the hunk causing the
regression.

Change-Id: I087cbe10280d4a60aa5ccfaefe24a223523fb3f2
Show notification on adb over network too

Screenshots - http://goo.gl/TgsRI6

Change-Id: I9ddc0aa9a4f330a06ab5d97a8645d1b31bb6f299

Conflicts:
	core/res/res/values/cm_strings.xml
	core/res/res/values/symbols.xml
	services/java/com/android/server/usb/UsbDeviceManager.java
HeadsUp: Clean up.

Change-Id: I98f445e7a4c92a34a3d9f63e14135e92416875ff