Leftovers after dcae5fac (improve speed of make check-world) in git tree with check-world

Hi all,

Since dcae5fac, we use a central path ($GIT_ROOT/tmp_install) to store
the installation deliverables during tests. Each module uses a
.gitignore with more or less those entries:
/log/
/results/
/tmp_check/

First note that /log/ is not used anymore, replaced by /tmp_check/log/
so we could just remove it. Also, as we do not ignore regression.diffs
and regression.out on purpose to check easily what has failed, what
about removing /tmp_check/ as well in those .gitignore files? It now
contains pgdata/ and log/, so it looks useful to me to show it with
git status to track it in case of failure as well.
Thoughts? Attached is a patch with all those files updated.
--
Michael