You increased the seriousness of this issue, with the result of upcoming autoremoval of galera-3 from Debian testing despite OpenSSL 1.1 not being available in testing yet, and not even in unstable yet. Galera-3 currently builds fine in testing and unstable.
Also the build problem with OpenSSL is not per se in Galera, but in libasio-dev. So if you want to have the status serious against something, make it against asio (https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=828239) and push the asio maintainer to release a new version of it, and then all other packages that depend on it will automatically be fixed.
