Fixed incorrect unregister from connectivity service

We should only unregister when the data connection is
not being handover or handover completed.

Fix: 160443926
Test: Manual
Merged-In: Idef20e1cd832623f8052e4701621f876b065ef6e
Change-Id: Idef20e1cd832623f8052e4701621f876b065ef6e
(cherry picked from commit 67918ee9)