The server side patchwork git hook to update patch status should be more efficient / smarter

[jnikula]

Normally performance isn't a problem when pushing a few commits; however when doing a backmerge from or a rebase on top of upstream, the push may contain hundreds or thousands of commits - most of which aren't tracked in the patchwork in question anyway. The git hook takes forever to handle these, and additionally transfering tons of error messages back to the client about not finding the patches.