KVM: fix syntax in input schema.

software/kvm/instance-kvm-resilient-input-schema.json

@@ -28,10 +28,10 @@
       "title": "Periodicity of backup",
       "description": "Periodicity of backup, in cron format.",
       "type": "string"
-    }
+    },
     "remove-backup-older-than": {
       "title": "Remove backups older than...",
-      "description": "Remove all the backups in PBS that are older than specified value. It should be rdiff-backup-compatible."
+      "description": "Remove all the backups in PBS that are older than specified value. It should be rdiff-backup-compatible.",
       "type": "string",
       "default": "3B"
     }