fix PostgreSQL procedure ordering

By doing it this way, we *should* avoid the gaps we were having
before. See also team#40776.

howto/upgrades/bullseye.md

@@ -203,12 +203,20 @@ PostgreSQL is special and needs to be upgraded manually.
         ssh bungei.torproject.org "mv /srv/backups/pg/meronense /srv/backups/pg/meronense-11 && sudo -u torbackup mkdir /srv/backups/pg/meronense"
 
  3. on the database server, possibly stop users of the database,
-    because it will have to be stopped for the major upgrade. on the
-    Bacula director, in particular, this probably means waiting for
-    all backups to complete and stopping the director:
+    because it will have to be stopped for the major upgrade.
+    
+    on the Bacula director, in particular, this probably means waiting
+    for all backups to complete and stopping the director:
     
         service bacula-director stop
 
+    this will mean other things on other servers! failing to stop
+    writes to the database *will* lead to problems with the backup
+    monitoring system. an alternative is to just stop PostgreSQL
+    altogether:
+    
+        service postgresql@11-main
+
  3. on the database server, do the actual cluster upgrade:
 
         export LC_ALL=C.UTF-8 &&
@@ -220,10 +228,6 @@ PostgreSQL is special and needs to be upgraded manually.
             mv /etc/postgresql/11/$cluster/conf.d/* /etc/postgresql/13/$cluster/conf.d/
         done
 
- 4. if services were stopped on step 3, restart them, e.g.:
- 
-        service bacula-director start
-
  4. change the cluster target in the backup system, in `tor-puppet`,
     for example:
 
@@ -239,6 +243,17 @@ PostgreSQL is special and needs to be upgraded manually.
                  pg_version => '13',
                }
 
+    ... and run Puppet on the server and the storage server (currently
+    `bungei`).
+
+ 4. if services were stopped on step 3, restart them, e.g.:
+ 
+        service bacula-director start
+ 
+    or:
+    
+        service postgresql@13-main start
+
  5. change the postgres version in `tor-nagios` as well:
 
         --- a/config/nagios-master.cfg