Fixes handover assert. Basically, an earlier patch changed the RTP packet size. 


git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@7154 19bc5d8c-e614-43d4-8b26-e1612bc8e597
Fix incorrect buffer management in send and rcv buffering.

git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@7258 19bc5d8c-e614-43d4-8b26-e1612bc8e597