Fixed corner case when handover fails

If handover fails, we need to tear down the existing
connection, so the new data connection can be
re-established on the new transport. If we leave the
existing data connection in current transport, then DCT
and qualified network service will be out of sync.

Bug: 131404118
Test: Manual
Change-Id: I074d4b20ab76365f587fb752e63a3b7390ba8e0b