PATCH: Uninitialized variable usage in contrib/pg_autovacuum

Sorry about the cross-post -- I'm not 100% sure which list this should be sent
to.

I noticed in the 7.4 release that in contrib/pg_autovacuum, args->logfile is
not initialized if a log file is not specified on the command line.  This
causes an immediate segfault on systems that fill allocated memory with some
value other than zero (my FreeBSD machine uses 0xD0).

Several crashes later I discovered that args->user, password, host, and port
are also used without being initialized.

This doesn't appear to be fixed in CVS and I came up empty on a mailing list
search -- hope it hasn't been reported already.

Attached is a quick patch that fixes the problem.

--
Craig