Telephony: Disable MSISDNEditPreference until init complete.

  - Avoids NPE. BACON-1832

Change-Id: I4a8919ecb3116375696f76e99c94b33ce961df41
Merge branch 'cm-11.0' of https://github.com/CyanogenMod/android_packages_services_Telephony into cm-11.0