pgsql: Have pg_upgrade create its output files in the current directory,

Log Message:
-----------
Have pg_upgrade create its output files in the current directory, rather
than in a subdirectory of the $HOME directory, or $TMP in Windows.

Modified Files:
--------------
    pgsql/contrib/pg_upgrade:
        check.c (r1.5 -> r1.6)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/contrib/pg_upgrade/check.c?r1=1.5&r2=1.6)
        dump.c (r1.1 -> r1.2)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/contrib/pg_upgrade/dump.c?r1=1.1&r2=1.2)
        function.c (r1.2 -> r1.3)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/contrib/pg_upgrade/function.c?r1=1.2&r2=1.3)
        option.c (r1.5 -> r1.6)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/contrib/pg_upgrade/option.c?r1=1.5&r2=1.6)
        pg_upgrade.c (r1.4 -> r1.5)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/contrib/pg_upgrade/pg_upgrade.c?r1=1.4&r2=1.5)
        pg_upgrade.h (r1.5 -> r1.6)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/contrib/pg_upgrade/pg_upgrade.h?r1=1.5&r2=1.6)
        version.c (r1.1 -> r1.2)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/contrib/pg_upgrade/version.c?r1=1.1&r2=1.2)
        version_old_8_3.c (r1.2 -> r1.3)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/contrib/pg_upgrade/version_old_8_3.c?r1=1.2&r2=1.3)