additional cleanups for pgport find_my_exec support

Clean up configure messaging and avoid a compiler warning by
checking for HAVE_PGPORT after config.h is included

Branch
------
REL_2_1_STABLE

Details
-------
http://git.postgresql.org/gitweb?p=slony1-engine.git;a=commitdiff;h=be933801d527caa7c88df622b6ec351668189281

Modified Files
--------------
RELEASE             |    3 ++-
config/acx_libpq.m4 |    4 +++-
src/slonik/slonik.c |   11 +++++++----
3 files changed, 12 insertions(+), 6 deletions(-)