zlib 1.2.12-r0 is not working with openjdk, it affects the checksum
calculation of the db migrations. It must be at least 1.2.12-r1. For
some reason joex has this newer version, but the restserver image not.
They are installed explicitely now on both images.
That's why the migration is now disabled on rest-server in the
docker-compose file. It is ok if this is run on one server. It can now
happen that on first start joex is migrating the db and the restserver
tries to do things that don't work yet - it is a corner case. This is
removed with the next version.
Refs: #1517
The missing dash resulted in solr sending a DNS query each minute that returned NxDomain.
In my case they looked like this: "f.base.domain" with base.domain being the base domain set for local DNS.
