Fixed that telephony notified the incorrect data connection state

Removed the notifyOffApnAvailability methods which incorrectly
notified the data connection state. Now the data connection state
will be notified when the connection actually goes to connected/
disconnected state, or some other special scenarios.

Test: Manual
Bug: 122938076
Change-Id: Ib28acc0ca489dccf867cb0745c669e587fd9cdb4