formatter: correct bool testing which should be __nonzero__ in Python 2

contrib/synthrepo: return None to delete files on commit, don't raise IOError The internal commit API was changed in 650b5b6e75ed to expect None from the filectx function when a file is to be deleted, not an IOError. This change keeps synthrepo up-to-date.

wix: contrib/sample.hgrc is no more

dockerrpm: create a yum/dnf repo from the generated rpms This gives "PPA" functionality where users easily can stay uptodate with latest nightly build.

docker: add CentOS 5 There is no official CentOS 5 docker template so we use one from saltstack.

docker: use stable tags for fedora and centos A moving target is rarely useful.

dockerrpm: prepare source outside docker and just run rpmbuild inside docker Simplifies the rpm build process. We will use platform specific rpmbuild directories and will not clean them and will drop the explicit copy to build directory.

dockerrpm: run docker build process as the current user, not as root Docker can be run by ordinary users if they are in the docker group. The build process would however be run as a root user, only protected by the sandboxing. That caused problems with the shared directory where rpmbuild would be picky about building from sources owned by less privileged users and producing files owned by root. Instead, add a build user with the right uid/gid to the image and run the docker process as that user.

dockerrpm: better handling of specification of docker name

dockerrpm: check that docker is running correctly before building