cleanup SCCP_CONFIG_NOUPDATENEEDED

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4522 43c1dc8c-776e-4df2-8ef1-6e829299be21
rename sccp_set_hold, add backgroundImage

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4523 43c1dc8c-776e-4df2-8ef1-6e829299be21