Fix: sccp_handle_keypadbutton when in CHANNELSTATE_DIALING or when pbx_run is running we should to force overlap dialing from that moment on. (Reported by Dan / Checked/Tested by Pavel).

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@5609 43c1dc8c-776e-4df2-8ef1-6e829299be21