qcow2: Avoid duplication in setting the refcount cache size

The refcount cache size does not need to be set to its minimum value in
read_cache_sizes(), as it is set to at least its minimum value in
qcow2_update_options_prepare().
Signed-off-by: NLeonid Bloch <lbloch@janustech.com>
Reviewed-by: NAlberto Garcia <berto@igalia.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

block/qcow2.c

@@ -834,10 +834,9 @@ static void read_cache_sizes(BlockDriverState *bs, QemuOpts *opts,
                                  (uint64_t)DEFAULT_L2_CACHE_CLUSTERS
                                  * s->cluster_size);
         }
-        if (!refcount_cache_size_set) {
-            *refcount_cache_size = min_refcount_cache;
-        }
     }
+    /* l2_cache_size and refcount_cache_size are ensured to have at least
+     * their minimum values in qcow2_update_options_prepare() */
 
     if (*l2_cache_entry_size < (1 << MIN_CLUSTER_BITS) ||
         *l2_cache_entry_size > s->cluster_size ||