If we can't get server name from client hello, get it from server certificate.
If we can't get server name from client hello, get it from server certificate.

vishnuvaradaraj/redwood,unixabg/redwood,vishnuvaradaraj/redwood,andybalholm/redwood,unixabg/redwood,yinheli/redwood-filter,yinheli/redwood-filter,yinheli/redwood-filter,andybalholm/redwood,vishnuvaradaraj/redwood