mark ganeti upgrade issue as resolved

We have a working howto now, so this is fixed. More issues crept up,
but I'll document them too.

howto/upgrades/bullseye.md

@@ -537,8 +537,6 @@ See also the official list of [known issues](https://www.debian.org/releases/bul
 
 ## Pending
 
- * Ganeti packages fail to upgrade (see above and [bug 993559][])
-
  * (from buster, needs confirmation:) upgrading restarts openvswitch
    will mean all guests lose network
 
@@ -568,6 +566,12 @@ See also the official list of [known issues](https://www.debian.org/releases/bul
 
 ## Resolved
 
+### Ganeti packages fail to upgrade
+
+This was reported as [bug 993559][], which is now marked as
+resolved. We nevertheless took care of upgrading to
+`bullseye-backports` first in the gnt-fsn cluster, which worked fine.
+
 ### Puppet configuration files updates
 
 The following configuration files were updated in Puppet to follow the