Enhancement: Set lastRedirectReason = 4 when call is being transfer -> Will show more detailed information in ReceiveCalls (Original Caller and Transferer records). (Supported in Information Gathering and Analyses by Philippe Teissier.). Callplane does not show the improvement that we hoped for though, which is a shame.

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@5662 43c1dc8c-776e-4df2-8ef1-6e829299be21