Fix support for auto redialing 911

Fix the IMS redial code so that it actually works on real networks --
the previous solution didn't work because the IMS stack will send the
380 through onCallTerminated, not onCallStartFailed.

Bug: 111235453
Test: manual (modify IMS stack locally to always return the 380 error
when dialing in airplane mode)

Change-Id: I37b6ac67c1459bf4e0d849333744bd2018970c97