Keyguard: Disable "Emergency call" button in OOS state

For CTA LAB new requirement, there should be no "Emergency call" on
lock screen in OOS state.

Do not show emergency button when service state is STATE_OUT_OF_SERVICE
and isEmergencyOnly is false since it can't make emergency call.

CRs-Fixed: 669191

Change-Id: I8fa68a449429508b801990c10f99615a1d71bb01