hashmap.h: remove unused variable

In 'hashmap_enable_item_counting()', item is assigned but never
used.  This causes a warning on HP NonStop.  As the variable is
never used, fix this by just removing it.

Signed-off-by: Randall S. Becker <rsbecker@nexbridge.com>
Helped-by: Thomas Gummerer <t.gummerer@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

hashmap.h

@@ -402,7 +402,6 @@ static inline void hashmap_disable_item_counting(struct hashmap *map)
  */
 static inline void hashmap_enable_item_counting(struct hashmap *map)
 {
-	void *item;
 	unsigned int n = 0;
 	struct hashmap_iter iter;
 
@@ -410,7 +409,7 @@ static inline void hashmap_enable_item_counting(struct hashmap *map)
 		return;
 
 	hashmap_iter_init(map, &iter);
-	while ((item = hashmap_iter_next(&iter)))
+	while (hashmap_iter_next(&iter))
 		n++;
 
 	map->do_count_items = 1;