Merge similar APNs together when loading All Apns.

They should have been merged together in the DB.  Do it now
at this convenient point so that we don't end up
making duplicate requests for the same apn.  That can lead
to duplicate calls with diff call IDs and then netd gets confuse
and things don't work.

bug:17634414
Change-Id: Ia77e43f53456f8ecadc9e94c20301fe8a52338d7