decom: Ignore orphan delete markers in verification stage (#21106)

To make sure that no objects were skipped for any reason,
decommissioning does a second phase of listing to check if there
are some objects that need to be decommissioned. However, the code
forgot to skip orphan delete markers since the decom code already
skips it.

Make the code ignore delete markers in in the verification phase.

Co-authored-by: Anis Eleuch <anis@min.io>

cmd/erasure-server-pool-decom.go

@@ -1182,29 +1182,32 @@ func (z *erasureServerPools) checkAfterDecom(ctx context.Context, idx int) error
 					return
 				}
 
+				// `.usage-cache.bin` still exists, must be not readable ignore it.
+				if bi.Name == minioMetaBucket && strings.Contains(entry.name, dataUsageCacheName) {
+					// skipping bucket usage cache name, as its autogenerated.
+					return
+				}
+
 				fivs, err := entry.fileInfoVersions(bi.Name)
 				if err != nil {
 					return
 				}
 
-				// We need a reversed order for decommissioning,
-				// to create the appropriate stack.
-				versionsSorter(fivs.Versions).reverse()
+				var ignored int
 
 				for _, version := range fivs.Versions {
 					// Apply lifecycle rules on the objects that are expired.
 					if filterLifecycle(bi.Name, version.Name, version) {
+						ignored++
 						continue
 					}
-
-					// `.usage-cache.bin` still exists, must be not readable ignore it.
-					if bi.Name == minioMetaBucket && strings.Contains(version.Name, dataUsageCacheName) {
-						// skipping bucket usage cache name, as its autogenerated.
+					if version.Deleted {
+						ignored++
 						continue
 					}
-
-					versionsFound++
 				}
+
+				versionsFound += len(fivs.Versions) - ignored
 			}); err != nil {
 				return err
 			}