Mms: Prevent popup window from closing

Popup window will close if pressed outside of it.

This commit disables touches outside the popup.

10x Revertron

Change-Id: Ife491d8b58d1b32d59760eb10a6e10cb67969974
Merge "Mms: Prevent popup window from closing" into cm-11.0
Merge branch 'cm-11.0' of https://github.com/CyanogenMod/android_packages_apps_Mms into android-4.4