DefineType: return base type OID, not its array

Event triggers want to know the OID of the interesting object created,
which is the main type.  The array created as part of the operation is
just a subsidiary object which is not of much interest.

src/backend/commands/typecmds.c

@@ -596,7 +596,7 @@ DefineType(List *names, List *parameters)
 	/* alignment must be 'i' or 'd' for arrays */
 	alignment = (alignment == 'd') ? 'd' : 'i';
 
-	typoid = TypeCreate(array_oid,		/* force assignment of this type OID */
+	TypeCreate(array_oid,		/* force assignment of this type OID */
 			   array_type,		/* type name */
 			   typeNamespace,	/* namespace */
 			   InvalidOid,		/* relation oid (n/a here) */