ma_check/mi_check: maria_repair_parallel initialization for !quick

end_io_call uses uninitialized values from the new_data_cache

As such we the buffer 0 and check this before calling end_io_cache on it.

Thanks Sergey Vojtovich for the review and for this solution.

Found by Coverity (ref 972481).

storage/maria/ma_check.c

@@ -4250,6 +4250,8 @@ int maria_repair_parallel(HA_CHECK *param, register MARIA_HA *info,
     }
   */
   DBUG_PRINT("info", ("is quick repair: %d", (int) rep_quick));
+  if (!rep_quick)
+    my_b_clear(&new_data_cache);
 
   /* Initialize pthread structures before goto err. */
   mysql_mutex_init(key_SORT_INFO_mutex, &sort_info.mutex, MY_MUTEX_INIT_FAST);
@@ -4608,7 +4610,7 @@ int maria_repair_parallel(HA_CHECK *param, register MARIA_HA *info,
     already or they were not yet started (if the error happend before
     creating the threads).
   */
-  if (!rep_quick)
+  if (!rep_quick && my_b_inited(&new_data_cache))
     end_io_cache(&new_data_cache);
   if (!got_error)
   {

storage/myisam/mi_check.c

@@ -2676,6 +2676,8 @@ int mi_repair_parallel(HA_CHECK *param, register MI_INFO *info,
   */
   DBUG_PRINT("info", ("is quick repair: %d", rep_quick));
   bzero((char*)&sort_info,sizeof(sort_info));
+  if (!rep_quick)
+    my_b_clear(&new_data_cache);
   /* Initialize pthread structures before goto err. */
   mysql_mutex_init(mi_key_mutex_MI_SORT_INFO_mutex,
                    &sort_info.mutex, MY_MUTEX_INIT_FAST);
@@ -3050,7 +3052,7 @@ int mi_repair_parallel(HA_CHECK *param, register MI_INFO *info,
     already or they were not yet started (if the error happend before
     creating the threads).
   */
-  if (!rep_quick)
+  if (!rep_quick && my_b_inited(&new_data_cache))
     (void) end_io_cache(&new_data_cache);
   if (!got_error)
   {