Fix a bug where our Motif ICE candidates were not quite proper, and make us more...

Fix a bug where our Motif ICE candidates were not quite proper, and make us more forgiving.

An issue was reported on the mailing list where calling would result in an "Incomplete
ICE-UDP candidate received on session" error message. This is the result of the ICE-UDP
candidate code not placing a "network" attribute within the candidates. This is now done.
To increase compatibility though I have removed the requirement for the "network" attribute
to exist within ICE-UDP candidates that are received since we don't actually require the
value.

Reported on the mailing list by Jean-Denis Girard.

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/11@375925 65c4cc65-6c06-0410-ace0-fbb531ad65f3