do not use directRTP if nat is set

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4606 43c1dc8c-776e-4df2-8ef1-6e829299be21
ILBC key/name/description mapping

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4607 43c1dc8c-776e-4df2-8ef1-6e829299be21
ILBC key/name/description mapping

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4608 43c1dc8c-776e-4df2-8ef1-6e829299be21
wrong rtp usage in sccp_rtp_set_phone

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4609 43c1dc8c-776e-4df2-8ef1-6e829299be21