Fix softkey endcall, on channel whith SCCP_CHANNELSTATE_DOWN (congested or otherwise).

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@5170 43c1dc8c-776e-4df2-8ef1-6e829299be21
Handle onhook, using provided lineInstance and callid. (Fixing issue where endcall button is required to hangup the call)

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@5171 43c1dc8c-776e-4df2-8ef1-6e829299be21