[volume.check.disk] fix wrong logic to compare

fix https://github.com/chrislusf/seaweedfs/issues/2626

minuend - subtrahend

weed/shell/command_volume_check_disk.go

@@ -138,9 +138,9 @@ func (c *commandVolumeCheckDisk) doVolumeCheckDisk(minuend, subtrahend *needle_m
 	// hash join, can be more efficient
 	var missingNeedles []needle_map.NeedleValue
 	var counter int
-	subtrahend.AscendingVisit(func(value needle_map.NeedleValue) error {
+	minuend.AscendingVisit(func(value needle_map.NeedleValue) error {
 		counter++
-		if _, found := minuend.Get(value.Key); !found {
+		if _, found := subtrahend.Get(value.Key); !found {
 			missingNeedles = append(missingNeedles, value)
 		}
 		return nil