Un-break building with BTREE_BUILD_STATS.

This has been broken for awhile, but not clear it's worth back-patching.

Euler Taveira de Oliveira

src/backend/access/nbtree/nbtree.c

@@ -31,6 +31,7 @@
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/smgr.h"
+#include "tcop/tcopprot.h"
 #include "utils/memutils.h"
 
 

src/backend/access/nbtree/nbtsort.c

@@ -70,6 +70,7 @@
 #include "access/nbtree.h"
 #include "miscadmin.h"
 #include "storage/smgr.h"
+#include "tcop/tcopprot.h"
 #include "utils/rel.h"
 #include "utils/tuplesort.h"