Change the logic to determine a conference call

Currently a call is declared as conference if there are more
than one connections for GSM and for CDMA based on the state
of the call.But actual logic should be based on the number of
ACTIVE connections in a call.

Change-Id: Ie0d67fe10c41e86716b8b39921c9a6269671582d
CRs-Fixed: 619901