Settings(MSIM): Disable MultiSimSettings activity if unsupported

* If this activity is launched on a non-multi-SIM it will crash.
* Because the activity is disabled, MultiSimSettings will become
  unavailable until the device is restarted.

Change-Id: I39eb1b41836833694be7469026abd95430691b52
Merge branch 'cm-10.2' into martincz