clean-up install directory on failure

[thibran]

In case of a failure when installing something, I would expect umake to clean-up all downloaded files and created folders, restoring somewhat the state pre-umake-installation.

E.g.:
When installing go using umake go to ~/.local/share/umake/go/go-lang, umake should delete ~/.local/share/umake/go/go-lang on failure.

[didrocks]

This is good and valid, thanks for the suggestion! This could be a good first contributor patch, will use it as such.

There is only one tricky thing to remember for whoever implements this: in case of a reinstall, if the failure happens before unpacking the archive, then, don't remove the directory. We need to decide if the failure happens during unpacking if we moved the initial directory content first to restore it or not (which could be an issue space-wise).