pgsql: Disallow gssapi authentication on local connections, since it

Log Message:
-----------
Disallow gssapi authentication on local connections, since it
requires a hostname to function.

Noted by Zdenek Kotala

Modified Files:
--------------
pgsql/src/backend/libpq:
hba.c (r1.201 -> r1.202)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/libpq/hba.c?r1=1.201&r2=1.202)