Two problems here:

1. When deactivating a data connection, what's the __+CREG__ response we get?
2. We have an uninvited unsolicited response __+CREG__ during the __AT+CGACT__ transaction.  However, in hardware/ril function [processLine()](https://github.com/mozilla-b2g/platform_hardware_ril/blob/master/reference-ril/atchannel.c#L241), it will be correctly processed at [line 261](https://github.com/mozilla-b2g/platform_hardware_ril/blob/master/reference-ril/atchannel.c#L261) because of a misuse of `at_send_command` in [requestSetupDataCall()](https://github.com/mozilla-b2g/platform_hardware_ril/blob/master/reference-ril/reference-ril.c#L1877).  Maybe file an follow-up for this.