Log Message:
-----------
Update schema USAGE permission description.
Modified Files:
--------------
pgsql/doc/src/sgml/ref:
grant.sgml (r1.56 -> r1.57)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/grant.sgml.diff?r1=1.56&r2=1.57)