Log Message:
-----------
Minor doc tweak: "NOT NULL" is redundant with "SERIAL" in example.
Modified Files:
--------------
pgsql/doc/src/sgml/ref:
create_domain.sgml (r1.26 -> r1.27)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_domain.sgml.diff?r1=1.26&r2=1.27)