Fix same schema to treat pg_constraint.confmatchtype = 'u' = 's'

Fix same schema to treat pg_constraint.confmatchtype = 'u' = 's'

This relates to a change in the character representing a simple match
on a foreign key stored in the confmatchtype field changing from 'u'
to 's' between postgresql 9.2 and 9.3. Ref:

	http://www.postgresql.org/docs/9.2/static/catalog-pg-constraint.html
	http://www.postgresql.org/docs/9.3/static/catalog-pg-constraint.html