Fix EmergencyCallHelper to always use the current phone object.
Fix EmergencyCallHelper to always use the current phone object.

EmergencyCallHelper could use the wrong phone object when called
on an encrypted device while it's changing from GSM to CDMA mode.
Remove local mPhone field and call mCM.getDefaultPhone() to get
the current phone object before each call.

Bug: 11561165
Change-Id: Ie6a23d78050f2dffbf92761e3ca0ee283e4192e3

md5555/android_packages_services_Telephony