fixes sccp video issue !!!!


git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4428 43c1dc8c-776e-4df2-8ef1-6e829299be21
Replace assert in sccp_socket_addDevice / sccp_socket_removeDevice with if check

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4429 43c1dc8c-776e-4df2-8ef1-6e829299be21
Retest d->session before calling sccp_session_removeDevice.

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4430 43c1dc8c-776e-4df2-8ef1-6e829299be21