Some more gitignore cleanups: cover contrib and PL regression test outputs.

Tom Lane <tgl@sss.pgh.pa.us>

Commit: cc2c8152e624e4985660e7042960bf300bb78a39
Author: Tom Lane <tgl@sss.pgh.pa.us>
Date: 2010-09-22T21:22:40Z
Releases: 9.1.0
Some more gitignore cleanups: cover contrib and PL regression test outputs.

Also do some further work in the back branches, where quite a bit wasn't
covered by Magnus' original back-patch.

Files