linters: Fix missing retired-on dates

There are a few projects that have been retired without
a retired-on date, this patch fixes them so they pass
the new gating on this:

- Charms[0][1]
- OpenStack UX[2]
- RefStack[3]

[0]: https://review.opendev.org/411217
[1]: https://review.opendev.org/596746
[2]: https://review.opendev.org/437957
[3]: https://review.opendev.org/590179

Change-Id: If9cb0a77c5d9365fb9aa4b998a0bacc75b2042e0

reference/legacy.yaml

@@ -54,16 +54,16 @@ Chef OpenStack:
   url: https://wiki.openstack.org/wiki/Chef
   partial: yes
   deliverables:
-    cookbook-openstack-bare-metal:
-      repos:
-        - openstack/cookbook-openstack-bare-metal
     cookbook-openstack-data-processing:
+      retired-on: 2016-12-21
       repos:
         - openstack/cookbook-openstack-data-processing
     cookbook-openstack-database:
+      retired-on: 2016-12-21
       repos:
         - openstack/cookbook-openstack-database
     cookbook-openstack-object-storage:
+      retired-on: 2016-12-21
       repos:
         - openstack/cookbook-openstack-object-storage
 
@@ -562,6 +562,7 @@ OpenStack UX:
     name: Piet Kruithof
     irc: Piet
     email: pkruithofjr@gmail.com
+  retired-on: 2017-02-24
   irc-channel: openstack-ux
   mission: >
     The mission of the UX Program is to help the teams improve the overall
@@ -1554,6 +1555,7 @@ RefStack:
     name: Chris Hoge
     irc: hogepodge
     email: chris@openstack.org
+  retired-on: 2018-08-10
   irc-channel: refstack
   service: Interoperability Test Report
   mission: >