Adding the ability for carrier app to override SPN and carrier name.
Adding the ability for carrier app to override SPN and carrier name.

The change allows system apps (holding MODIFY_PHONE_STATE permission) or
carrier apps to override the "carrier branding" on a per ICCID basis. The
override affects the service provider name as well as the network operator
name. The override is also saved as a SharedPreference and will persist for
the iccId across reboots.

Change-Id: I985ba247e10e2501e3d0d21567ccadc46f365879

md5555/android_packages_services_Telephony