Mms: Clean up delivery report dialog.

Instead of launching another activity just to show the delivery report,
mimic how showMessageDetails works instead, using AlertDialog.Builder.
This ports the dialog over to Holo as well.

Signed-off-by: angelsl <hidingfromhidden@gmail.com>
Change-Id: Ia7ee549fe7ed9770a70482a042ebbc4bc12bab21