Fix 'Tell ... to send RTP/UDP media' debug output. Use SCCP_PACKET_HEADER in sccp_build_packet instead of magic value 12

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4279 43c1dc8c-776e-4df2-8ef1-6e829299be21
Fix 'Tell ... to send RTP/UDP media' debug output. Use SCCP_PACKET_HEADER in sccp_build_packet instead of magic value 12

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4280 43c1dc8c-776e-4df2-8ef1-6e829299be21