Mms: Clear notifications and mark messages read in certain situations

I made these changes to CarbonRom (a fork of CM11), and I
heard that people were still having these issues in CM11.
These two commits (merged into one here) fix issues where messages
in the Mms app were not getting marked as read in certain situations,
and the notification was not getting cleared when tapped.

More details about these bugs can be found in my original commits to
Carbon:

https://github.com/CarbonDev/android_packages_apps_Mms/commit/b3a831a6e3019d256163b23870e0f4e0134fce16

https://github.com/CarbonDev/android_packages_apps_Mms/commit/21c851e139c56f387c83e11d12d2a2fa8e0c3ff0

Change-Id: I4dde340157c158c26488fed66c10c263e1c28664