msc_mgcp: to not access higher layers after release

The higher layers (gsm_04_08.c) are informed errors occur. But it
is not checked if the call was already released. If an error occurs
after the call control stack calls msc_mgcp_call_release() then
the higher layers might already have cleaned up and the code
accesses memory that is already freed (trans)

- fix use after free by guarding the call to mncc_tx_to_cc()

Change-Id: I78f1b6a9149488a4ad3f120c1e190a83c07d4b89
Related OS#2881
Related OS#2882
1 file changed