Fix concurrency bug w\ all apn list in DcTracker

Concurrency issue was caused by modifications to the all apn
list while being read from within getPreferredApn() on a
thread handler other than dcHandlerThread.  We are now
calling getPreferredApn() on dcHandlerThread and passing the
result to dataConnection.bringUp through ConnectionParams

Test: Accessed internet through mobile and wifi
Test: Popped sim and out while testing data connection
Test: Placed \ Received voice call
Test: Send \ Received sms
Bug: 147260061
Change-Id: I927fd5ac5783d601e21f9c7af508524246bbd699