Log Message:
-----------
Update GRANT USAGE on schema permission description.
Modified Files:
--------------
pgsql/doc/src/sgml/ref:
grant.sgml (r1.57 -> r1.58)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/grant.sgml.diff?r1=1.57&r2=1.58)