Fixed data disconnected during handover

Data call list changed event was deferred during
handover, and then triggered network disconnected
when the deferred message got processed.

Fixed by conditionally dropping the unrelated
data call list changed event, and only defer the
related one.

Test: Manual
Fix: 216085900
Change-Id: Icf754443719c0798b843feddd8f34f07cb5fac8b
Merged-In: Icf754443719c0798b843feddd8f34f07cb5fac8b