pg_regress: stat correct paths

Hi,

I think I have found a small problem in pg_regress.

In convert_sourcefiles() it stats directories based on the current
working directory, but in convert_sourcefiles_in() it reads files based
in srcdir or abs_builddir.

The attached patch changes the behavior of pg_regress, so that it stats
the directories that it read the files from. This patch will also make
pg_regress fail if the directories are missing, instead of silently
ignoring the missing directories. If you think this fail-fast behavior
is undesirable, I can create a patch that just ignores the files (todays
behavior), or ignores them with a warning.

The attached patch is tested by running pg_regress in a non-standard
path and by running "make check", both on Solaris Nevada on x64.

-J
--

Jørgen Austvik, Software Engineering - QA
Sun Microsystems Database Technology Group