Refer to the default foreign key match style as MATCH SIMPLE internally.

Previously we followed the SQL92 wording, "MATCH <unspecified>", but since
SQL99 there's been a less awkward way to refer to the default style.

In addition to the code changes, pg_constraint.confmatchtype now stores
this match style as 's' (SIMPLE) rather than 'u' (UNSPECIFIED).  This
doesn't affect pg_dump or psql because they use pg_get_constraintdef()
to reconstruct foreign key definitions.  But other client-side code might
examine that column directly, so this change will have to be marked as
an incompatibility in the 9.3 release notes.

src/include/catalog/catversion.h

@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	201206141
+#define CATALOG_VERSION_NO	201206171
 
 #endif

src/include/nodes/parsenodes.h

@@ -1514,7 +1514,7 @@ typedef enum ConstrType			/* types of constraints */
 /* Foreign key matchtype codes */
 #define FKCONSTR_MATCH_FULL			'f'
 #define FKCONSTR_MATCH_PARTIAL		'p'
-#define FKCONSTR_MATCH_UNSPECIFIED	'u'
+#define FKCONSTR_MATCH_SIMPLE		's'
 
 typedef struct Constraint
 {
@@ -1550,7 +1550,7 @@ typedef struct Constraint
 	RangeVar   *pktable;		/* Primary key table */
 	List	   *fk_attrs;		/* Attributes of foreign key */
 	List	   *pk_attrs;		/* Corresponding attrs in PK table */
-	char		fk_matchtype;	/* FULL, PARTIAL, UNSPECIFIED */
+	char		fk_matchtype;	/* FULL, PARTIAL, SIMPLE */
 	char		fk_upd_action;	/* ON UPDATE action */
 	char		fk_del_action;	/* ON DELETE action */
 	List	   *old_conpfeqop;	/* pg_constraint.conpfeqop of my former self */