Call "createConnectionComplete" callback in Telecom.

When done creating a connection in Telecom, call createConnectionComplete.
Note: Checks the serviceinterface for null since in the case of a
"null connection" from the ConnectionService we'll be unbound by
the time we get here.

Test: Manual
Bug: 33272455
Change-Id: Ic23f6ad65d49d2a8c70ac4d35d53feb0dd5e34bb