Affects Version/s: None
Fix Version/s: 0.10.0
A Docker build step for apt-get mono often fails on CI due to unknown reasons.
In an tentative attempt to alleviate this, we can remove unneeded apt packages and reduce download payload.
- mono-complete was not necessary, mono-devel suffices
- we do not use xbuild and gmcs
- rake was already available without gem install rake. Also this somehow caused problem on Ubuntu Xenial.
- skip ruby doc for bundler as is often seen
- update-alternative java was for previous versions of Ubuntu and resulted in error message because no alternative is there