Merge commit 'b6432ca4a090c02a07038f926e9e514d8cb1b657' * commit 'b6432ca4a090c02a07038f926e9e514d8cb1b657': SipService: unset session listener if listener is gone.
Merge commit 'b6432ca4a090c02a07038f926e9e514d8cb1b657' * commit 'b6432ca4a090c02a07038f926e9e514d8cb1b657': SipService: unset session listener if listener is gone.