Fix unused variable warnings

Author: Nikita Glukhov

jsquery_op.c

@@ -449,7 +449,7 @@ recursiveExecute(JsQueryItem *jsq, JsonbValue *jb, JsQueryItem *jsqLeftArg)
 			if (JsonbType(jb) == jbvScalar)
 			{
 				JsonbIterator	*it;
-				int32			r;
+				int32			r PG_USED_FOR_ASSERTS_ONLY;
 				JsonbValue		v;
 
 				it = JsonbIteratorInit(jb->val.binary.data);
@@ -572,7 +572,7 @@ recursiveExecute(JsQueryItem *jsq, JsonbValue *jb, JsQueryItem *jsqLeftArg)
 			if (JsonbType(jb) == jbvScalar)
 			{
 				JsonbIterator	*it;
-				int32			r;
+				int32			r PG_USED_FOR_ASSERTS_ONLY;
 				JsonbValue		v;
 
 				it = JsonbIteratorInit(jb->val.binary.data);