IMS: merge option not shown after srvcc

After srvcc, conferenceable property set by the Telephony connection
service is getting overridden by Ims conference controller. So remove
the connection from Ims conference controller after adding it to
Telephony conference controller.

Bug: 21953444
Change-Id: I5e4ec8b8c7c96f4d8049344beaa117b976db9cea
1 file changed