Add BKI_DEFAULT to pg_class.relrewrite

This column is always 0 on disk, so it doesn't have to be tracked
separately for each entry.

src/include/catalog/pg_class.dat

@@ -27,9 +27,9 @@
   relpersistence => 'p', relkind => 'r', relnatts => '31', relchecks => '0',
   relhasrules => 'f', relhastriggers => 'f', relhassubclass => 'f',
   relrowsecurity => 'f', relforcerowsecurity => 'f', relispopulated => 't',
-  relreplident => 'n', relispartition => 'f', relrewrite => '0',
-  relfrozenxid => '3', relminmxid => '1', relacl => '_null_',
-  reloptions => '_null_', relpartbound => '_null_' },
+  relreplident => 'n', relispartition => 'f', relfrozenxid => '3',
+  relminmxid => '1', relacl => '_null_', reloptions => '_null_',
+  relpartbound => '_null_' },
 { oid => '1249',
   relname => 'pg_attribute', reltype => 'pg_attribute', relam => 'heap',
   relfilenode => '0', relpages => '0', reltuples => '0', relallvisible => '0',
@@ -37,9 +37,9 @@
   relpersistence => 'p', relkind => 'r', relnatts => '24', relchecks => '0',
   relhasrules => 'f', relhastriggers => 'f', relhassubclass => 'f',
   relrowsecurity => 'f', relforcerowsecurity => 'f', relispopulated => 't',
-  relreplident => 'n', relispartition => 'f', relrewrite => '0',
-  relfrozenxid => '3', relminmxid => '1', relacl => '_null_',
-  reloptions => '_null_', relpartbound => '_null_' },
+  relreplident => 'n', relispartition => 'f', relfrozenxid => '3',
+  relminmxid => '1', relacl => '_null_', reloptions => '_null_',
+  relpartbound => '_null_' },
 { oid => '1255',
   relname => 'pg_proc', reltype => 'pg_proc', relam => 'heap',
   relfilenode => '0', relpages => '0', reltuples => '0', relallvisible => '0',
@@ -47,9 +47,9 @@
   relpersistence => 'p', relkind => 'r', relnatts => '29', relchecks => '0',
   relhasrules => 'f', relhastriggers => 'f', relhassubclass => 'f',
   relrowsecurity => 'f', relforcerowsecurity => 'f', relispopulated => 't',
-  relreplident => 'n', relispartition => 'f', relrewrite => '0',
-  relfrozenxid => '3', relminmxid => '1', relacl => '_null_',
-  reloptions => '_null_', relpartbound => '_null_' },
+  relreplident => 'n', relispartition => 'f', relfrozenxid => '3',
+  relminmxid => '1', relacl => '_null_', reloptions => '_null_',
+  relpartbound => '_null_' },
 { oid => '1259',
   relname => 'pg_class', reltype => 'pg_class', relam => 'heap',
   relfilenode => '0', relpages => '0', reltuples => '0', relallvisible => '0',
@@ -57,8 +57,8 @@
   relpersistence => 'p', relkind => 'r', relnatts => '33', relchecks => '0',
   relhasrules => 'f', relhastriggers => 'f', relhassubclass => 'f',
   relrowsecurity => 'f', relforcerowsecurity => 'f', relispopulated => 't',
-  relreplident => 'n', relispartition => 'f', relrewrite => '0',
-  relfrozenxid => '3', relminmxid => '1', relacl => '_null_',
-  reloptions => '_null_', relpartbound => '_null_' },
+  relreplident => 'n', relispartition => 'f', relfrozenxid => '3',
+  relminmxid => '1', relacl => '_null_', reloptions => '_null_',
+  relpartbound => '_null_' },
 
 ]

src/include/catalog/pg_class.h

@@ -117,7 +117,7 @@ CATALOG(pg_class,1259,RelationRelationId) BKI_BOOTSTRAP BKI_ROWTYPE_OID(83,Relat
 	bool		relispartition;
 
 	/* heap for rewrite during DDL, link to original rel */
-	Oid			relrewrite;
+	Oid			relrewrite BKI_DEFAULT(0);
 
 	/* all Xids < this are frozen in this rel */
 	TransactionId relfrozenxid;