1) a=ice-options can be a session-level attribute. Use the correct
lookup function to check for both media-level and session-level
attributes.
2) The RTP endpoint address must be filled in before we do the trickle
ICE check, which uses 0.0.0.0:9 as determining factor.
3) Adapt a test case.
Change-Id: Ic0caffc85791131173848d28f5a652ad9d9124db