Fix free_sdp() : don't try to free part of a sip_msg structure (bug introduced by commit bde8c0a045 )
Revert "Fix free_sdp() : don't try to free part of a sip_msg structure (bug introduced by commit bde8c0a045 )"

This reverts commit 259a41f98d6fad69b0ac291c2d9b7411fb8c5791.
Merge branch 'master' of github.com:csollet/opensips