Fix "Remove superfluous tqual.h includes" by adding back one include.

I removed one include too many in e7cc78ad, not sure why that
escaped my test script.

Author: Andres Freund

src/backend/catalog/catalog.c

@@ -48,6 +48,7 @@
 #include "utils/fmgrprotos.h"
 #include "utils/rel.h"
 #include "utils/syscache.h"
+#include "utils/tqual.h"
 
 
 /*