The build script is always returning success

The problem

The outcome of the build process is returned here:

https://forge.etsi.org/rep/mec/gs032p3-ttcn-test-suite/blob/master/docker/run-container.sh#L15

As it is right now always returns 0, meaning the build is always successful.

Proposed change

The build need to know whether the compilation is correct or not and to escalate the outcome all the way to the main script, i.e. .jenkins.sh