Merge branch 'w/8.6/bugfix/CLDSRV-413/crr_existing_null_version' into…

… tmp/octopus/w/8.7/bugfix/CLDSRV-413/crr_existing_null_version

lib/routes/routeBackbeat.js

@@ -511,7 +511,7 @@ function putMetadata(request, response, bucketInfo, objMd, log, callback) {
             if (!versionId) {
                 omVal.isNull = true;
                 if (versioning) {
-                    // If the null version does not have a version id, it is a current null version.
+                    // If the null version does not have a version id, it can only be a unique current null version.
                     // To update the metadata of a current version, versioning is set to false.
 
                     // This condition is to handle the case where a single null version looks like a master
@@ -520,6 +520,7 @@ function putMetadata(request, response, bucketInfo, objMd, log, callback) {
                     // and then convert bucket to versioned.
                     // If no new versioned objects are added for given object(s), they look like
                     // standalone master keys.
+                    // If a new version is added then an internal versionId would be generated for the null version.
                     versioning = false;
                 } else {
                     const versioningConf = bucketInfo.getVersioningConfiguration();