Fix #include problems in 9.1 branch.

Remove unnecessary and circular #include of syncrep.h from proc.h.
Add htup.h to tablecmds.h so it will compile without prerequisites.

Author: tglsfdc

src/include/commands/tablecmds.h

@@ -14,6 +14,7 @@
 #ifndef TABLECMDS_H
 #define TABLECMDS_H
 
+#include "access/htup.h"
 #include "nodes/parsenodes.h"
 #include "storage/lock.h"
 #include "utils/relcache.h"

src/include/storage/proc.h

@@ -15,7 +15,6 @@
 #define _PROC_H_
 
 #include "access/xlog.h"
-#include "replication/syncrep.h"
 #include "storage/latch.h"
 #include "storage/lock.h"
 #include "storage/pg_sema.h"