scrubber: Deactivate the unneeded objstorage configuration part

A current implementation detail imposes to define an objstorage key in the storage key entry. It's not needed for the current checker service so use a noop key entry for the objstorage.

Related to T4324

Test Plan

octo-diff drops the azure objstorage configuration and use a noop objstorage (unused anyway):

$ $SWH_PUPPET_ENVIRONMENT_HOME/bin/octocatalog-diff --octocatalog-diff-args --no-truncate-details --to staging scrubber1.internal.softwarehe
ritage.org
Found host scrubber1.internal.softwareheritage.org
...
*******************************************
  File[/etc/softwareheritage/scrubber/postgres.yml] =>
   parameters =>
     content =>
      @@ -13,74 +13,4 @@
           - cls: filtered
             storage_conf:
      -        cls: azure-prefixed
      -        accounts:
      -          '0':
      -            account_name: 0euwestswh
      -            api_secret_key: swh::azure::credentials::0euwestswh
      -            container_name: contents
      -          '1':
      -            account_name: 1euwestswh
      -            api_secret_key: swh::azure::credentials::1euwestswh
      -            container_name: contents
      -          '2':
      -            account_name: 2euwestswh
      -            api_secret_key: swh::azure::credentials::2euwestswh
      -            container_name: contents
      -          '3':
      -            account_name: 3euwestswh
      -            api_secret_key: swh::azure::credentials::3euwestswh
      -            container_name: contents
      -          '4':
      -            account_name: 4euwestswh
      -            api_secret_key: swh::azure::credentials::4euwestswh
      -            container_name: contents
      -          '5':
      -            account_name: 5euwestswh
      -            api_secret_key: swh::azure::credentials::5euwestswh
      -            container_name: contents
      -          '6':
      -            account_name: 6euwestswh
      -            api_secret_key: swh::azure::credentials::6euwestswh
      -            container_name: contents
      -          '7':
      -            account_name: 7euwestswh
      -            api_secret_key: swh::azure::credentials::7euwestswh
      -            container_name: contents
      -          '8':
      -            account_name: 8euwestswh
      -            api_secret_key: swh::azure::credentials::8euwestswh
      -            container_name: contents
      -          '9':
      -            account_name: 9euwestswh
      -            api_secret_key: swh::azure::credentials::9euwestswh
      -            container_name: contents
      -          a:
      -            account_name: aeuwestswh
      -            api_secret_key: swh::azure::credentials::aeuwestswh
      -            container_name: contents
      -          b:
      -            account_name: beuwestswh
      -            api_secret_key: swh::azure::credentials::beuwestswh
      -            container_name: contents
      -          c:
      -            account_name: ceuwestswh
      -            api_secret_key: swh::azure::credentials::ceuwestswh
      -            container_name: contents
      -          d:
      -            account_name: deuwestswh
      -            api_secret_key: swh::azure::credentials::deuwestswh
      -            container_name: contents
      -          e:
      -            account_name: eeuwestswh
      -            api_secret_key: swh::azure::credentials::eeuwestswh
      -            container_name: contents
      -          f:
      -            account_name: feuwestswh
      -            api_secret_key: swh::azure::credentials::feuwestswh
      -            container_name: contents
      -      filters_conf:
      -      - type: readonly
      -    - cls: filtered
      -      storage_conf:
      -        cls: remote
      -        url: http://banco.internal.softwareheritage.org:5003/
      -      filters_conf:
      -      - type: readonly
      -    - cls: filtered
      -      storage_conf:
      -        cls: remote
      -        url: http://saam.internal.softwareheritage.org:5003/
      -      filters_conf:
      -      - type: readonly
      +    cls: noop

*******************************************
*** End octocatalog-diff on scrubber1.internal.softwareheritage.org

Manually updating the configuration in the node and starting one service, it's happy as is:

17:25:13 swh-scrubber@belvedere:5432=> select now(), count(*) from corrupt_object ;
+-------------------------------+-------+
|              now              | count |
+-------------------------------+-------+
| 2022-06-27 15:25:20.101532+00 |   139 |
+-------------------------------+-------+
(1 row)

Time: 5.087 ms

---

Migrated from D8041 (view on Phabricator)