BT: Send proper updates to headset for call swap.

In gsm network, when active and held calls are swapped, firstly
active call is put to hold making held call count as 2 and
BluetoothPhoneService updates callheld indicator as no call active.
After this next update comes to make original held call as active
and again callheld indicator as active and held is updated.
Avoid unnecessary first update to headset.
In cdma network, send callheld indicator for call swap within
active conference.

CRs-Fixed: 758732
Change-Id: Idc66a90b18391f53f196567b6f6e149b11ce11c8