Fix collprovider of predefined collations

An earlier version of the patch had collprovider as an integer and thus
set these to 0, but the correct setting is now null.

Author: petere

src/include/catalog/catversion.h

@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	201706081
+#define CATALOG_VERSION_NO	201706131
 
 #endif

src/include/catalog/pg_collation.h

@@ -70,13 +70,13 @@ typedef FormData_pg_collation *Form_pg_collation;
  * ----------------
  */
 
-DATA(insert OID = 100 ( default		PGNSP PGUID d -1 "" "" 0 ));
+DATA(insert OID = 100 ( default		PGNSP PGUID d -1 "" "" _null_ ));
 DESCR("database's default collation");
 #define DEFAULT_COLLATION_OID	100
-DATA(insert OID = 950 ( C			PGNSP PGUID c -1 "C" "C" 0 ));
+DATA(insert OID = 950 ( C			PGNSP PGUID c -1 "C" "C" _null_ ));
 DESCR("standard C collation");
 #define C_COLLATION_OID			950
-DATA(insert OID = 951 ( POSIX		PGNSP PGUID c -1 "POSIX" "POSIX" 0 ));
+DATA(insert OID = 951 ( POSIX		PGNSP PGUID c -1 "POSIX" "POSIX" _null_ ));
 DESCR("standard POSIX collation");
 #define POSIX_COLLATION_OID		951