Investigate memory leak

A dirauth that recently tried sbws 1.0 and run munin in the same machine detected a memory leak.

We run munin in longclaw's sbws 1.2 and the memory leak is still there. Certainly we've never worked on that.

I know of several points in the code where this might be happening, like copying list of relay classes or measurements and the storage/load of KeyValues, which also caused #40020 (closed).

Maybe #40084 (closed) or #40086 (closed) is related to this.

I hope that finding/solving this is not more time consuming than switching to #40024 (closed).