Changes

ttcn3-bsc-test: Fix ttcn3-bsc_sccplite-latest

Re-add the msc 0->mgw config line since the "latest" version of osmo-bsc still uses
it. This was probably caused by fixing fallout from osmo-bsc.git commit
da4af65a51ee8b8d7b380330c0301de293347563 in master.

The config line is ignored in master so should be safe to keep until a
new osmo-bsc version is released.

Change-Id: I85231bf66a78232567eb91b92b8542ca7f728beb