regression.diff wrong dir name

Hi all,

Something minor, but when you do a "make check" from the main source
directory and it finishes, it mentions that the regression.diff file is
in ./regression.diff

It's really at src/test/regress/regression.diff, and although not hard
to figure out (it's a carry-over from pre 7.1), it might be confusing to
people to new PostgreSQL.

Regards and best wishes,

Justin Clift