This patch adds a new 'ignoresdpversion' option to sip.conf. When this is

enabled (either globally or for a specific peer), chan_sip will treat any SDP
data it receives as new data and update the media stream accordingly.  By
default, Asterisk will only modify the media stream if the SDP session version
received is different from the current SDP session version.  This option is
required to interoperate with devices that have non-standard SDP session
version implementations (observed by toc on the bug tracker with Microsoft OCS
which always uses 0 as the session version).

http://reviewboard.digium.com/r/94/
(closes issue #13958)
Reported by: toc
Tested by: toc


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@165180 65c4cc65-6c06-0410-ace0-fbb531ad65f3