Telephony: Dismissable voicemail notifications

Ported from cm-10.2:
http://review.cyanogenmod.org/#/c/35023

Change-Id: Iccd01210cdd9a43167392fc09debbfc4cb23b6f6
Merge branch 'cm-11.0' of git://github.com/CyanogenMod/android_packages_services_Telephony into kk44