Merge pull request #15654 from jaoo/962453

Bug 962453 - [DSDS] Once visit APN setting of one SIM, same APN of another SIM will be changed to "Custom". r=arthurcc(cherry picked from commit 4d0b2ffaf044a20b5bea9d7d85d4ecc5a71080fd)

Conflicts:
	apps/settings/elements/carrier_data_settings.html
	apps/settings/elements/carrier_mms_settings.html
	apps/settings/elements/carrier_supl_settings.html