Retest d->session before calling sccp_session_removeDevice.

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4431 43c1dc8c-776e-4df2-8ef1-6e829299be21
Fix line release during sccp_channel_find_on_device_bypassthrupartyid

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4432 43c1dc8c-776e-4df2-8ef1-6e829299be21