Automatic pending bugs tagging

[Emmanuel Bourg <ebourg@apache.org>]

Hi all,

I aligned the post-receive hook of our Git repositories on the one used
by the Perl Team, and it's now able to tag automatically the bugs as
pending when a commit fixes them. It also appends a message to the bug
with a reference to the commit.

Here is an example:

    https://bugs.debian.org/828451#14

The hook detects a bug reference in the commit messages, for example:
(Closes: #828451). It doesn't check the content of debian/changelog, so
the reference must be included in the commit message.

Enjoy :)

Emmanuel Bourg