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

Merged-In: Ib28acc0ca489dccf867cb0745c669e587fd9cdb4
Change-Id: Ib28acc0ca489dccf867cb0745c669e587fd9cdb4
(cherry picked from commit 2cb46f56)