The ttcn3-*-{start,stop}.sh scripts include a file from the _scripts dir since Ia63c37b54fb42a8c64a676334cef6f9df4152e18. As they are called through symlinks in / in docker-playground.git, we must make the another symlink available for _scripts as well.
Fix for: ../ttcn3-tcpdump-start.sh: 3: .: cannot open ../_scripts/tcpdump-dumpcap.inc.sh: No such file
