Improves setting of the stream direction when processing jingle content-accept messages. This fixes a problem with video conferences where video streams sometimes 'freeze' if a non-focus starts to send video (while the focus is not sending video)

git-svn-id: https://svn.java.net/svn/jitsi~svn/libjitsi@10752 198c5059-ef06-4ec0-9a75-fdd6b0ef00a6