rbd-mirror: fix syncing_percent calculation logic in get_replay_status()
When a snapshot sync is resumed and the get_replay_status function
is called before handle_copy_image_progress, the syncing_percent
value may be greater than 100 as the m_local_object_count is still
set to zero. This commit sets the syncing_percent to 0 in such cases.
Fixes: https://tracker.ceph.com/issues/58706 Signed-off-by: N Balachandran <nibalach@redhat.com>