.gitignore: allow debian .patch files
The Ubuntu packaging layout with git-buildpackage assumes a
"debian/patches/" directory with several .patch files in it.
When upstream's .gitignore tells Git to ignore .patch files, we have to
edit that line out downstream. When we forget to do that downstream, it
can lead to missing patches and broken downstream builds.
Allow patches in the /debian/patches directory so it's easier to
maintain an Ubuntu package based on upstream's Git repo.
Signed-off-by: Ken Dreyer <kdreyer@redhat.com>
(cherry picked from commit
c734b0c0296152721b658af7b699a64b3a49d251)