Log Message:
-----------
CREATE DOMAIN ... DEFAULT NULL failed because gram.y special-cases DEFAULT
NULL and DefineDomain didn't. Bug goes all the way back to original coding
of domains. Per bug #3396 from Sergey Burladyan.
Modified Files:
--------------
pgsql/src/backend/commands:
typecmds.c (r1.105 -> r1.106)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/typecmds.c.diff?r1=1.105&r2=1.106)