Please consider merging branch defaultbranch of repo https://git.spwhitton.name/propellor.
This branch adds a new property Git.bareRepoDefaultBranch which sets the default branch of a bare repository. This is useful when hosting git repositories that don't have a master branch, so that something gets checked out when someone clones them.
I limited this property to bare repositories since the notion of a default branch for a non-bare repository doesn't really make sense.