Fix a loss of data.

Fix a bug in DataConnection state machine where the notification
of disconnection completion was sent before we actually transitioned
to the in active state. Also, change conn.reset to send a response
so the user can know when the transition to the in active state
completes for that also.

bug: 2471897
Change-Id: I5776324ac89a607925d07f4a600bc5b34c3f3ed6