mgr: If the requested OSD is down don't trust osd_stat info

If we have a down AND out OSD it may contains osd_stat with num_pgs == 0.
When all PGs aren't active+clean we need an accurate value or we consider
the osd missing stat info.

Fixes: https://tracker.ceph.com/issues/38930

Signed-off-by: David Zafman <dzafman@redhat.com>
(cherry picked from commit 97f3b7c)

src/mgr/DaemonServer.cc

@@ -1393,7 +1393,7 @@ bool DaemonServer::_handle_command(
 	  if (num_active_clean < pg_map.num_pg) {
 	    // all pgs aren't active+clean; we need to be careful.
 	    auto p = pg_map.osd_stat.find(osd);
-	    if (p == pg_map.osd_stat.end()) {
+	    if (p == pg_map.osd_stat.end() || !osdmap.is_up(osd)) {
 	      missing_stats.insert(osd);
 	      continue;
 	    } else if (p->second.num_pgs > 0) {