Settings: DUT can register on a forbidden network operator

In NetworkSetting.java, when networksListLoaded() is called,
it disabled the FORBIDDEN Preferences. But when tap the
available one to register it done, the FORBIDDEN Preferences
will be enabled again by invalidate() operation.

After selection operation is done, we should disable FORBIDDEN
preferences again when receive an EVENT_NETWORK_SELECTION_DONE
message in NetworkSetting.java.

CRs-Fixed: 529690

Change-Id: Ie27823f5165882102e206107a21357d7482f5d2c