Doing a chdir in the parent is evil. For instance, we had Hydra core
dumps ending up in the cloned directory. Therefore, the function
‘run’ allows doing a chdir in the child. The function ‘grab’ returns
the child's stdout and throws an exception if the child fails.
HipChat notification messages now say which committers were
responsible, e.g.
Job patchelf:trunk:tarball: Failed, probably due to 2 commits by Eelco Dolstra
