Fix: scheduled hangup (references #220, references #221, references #223, references #224)

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@5714 43c1dc8c-776e-4df2-8ef1-6e829299be21
Enhancement: Store callforward information into astdb once by device/line and once by line/device. (Reported and Patch (p2_v2) provided by Nikolay Vasilev)

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@5715 43c1dc8c-776e-4df2-8ef1-6e829299be21