Fix fatal crash in Settings(Phone Status) for secondary user

Switch to secondary user-> About Phone->Status. Settings crashes

SubscriptionController.getInstance will be null for secondary user
as Phone information is not provided for secondary user. Further
both SIM status and IMEI should also be removed from Status screen
as they will again throw IllegalStateException as no Default Phone
is available for secondary user.
A simple fix is to check for current user before calling
SubscriptionController and removing SIM status and IMEI from
preferences for the secondary user.

Change-Id: I5a9607e83673afa8c7de0ed6ca6767ebf79e9cb8