support of more then 255 tables dependence in query cache (fixed BUG#930)

mysql-test/r/query_cache.result:
  test of many merged tales
mysql-test/t/query_cache.test:
  test of many merged tales
sql/sql_cache.h:
  query with merged tables can depend of more then 255 tables

sql/sql_cache.h

@@ -61,7 +61,7 @@
 #define QUERY_CACHE_PACK_ITERATION		2
 #define QUERY_CACHE_PACK_LIMIT			(512*1024L)
 
-#define TABLE_COUNTER_TYPE uint8
+#define TABLE_COUNTER_TYPE uint
 
 struct Query_cache_block;
 struct Query_cache_block_table;