Make sure mysql_version is available on first puppet run

Dockerfile

@@ -35,6 +35,9 @@ RUN sed -i "s@__WEBLATE_URL__@${weblate_url}@" /etc/puppet/hiera/common.yaml
 # /etc/sysctl.conf must be present
 RUN apt-get -y install procps
 
+# install mysql server so mysql_version is available during first puppet run
+RUN DEBIAN_FRONTEND=noninteractive apt-get -y install mysql-server
+
 # apply puppet recipes!
 RUN puppet apply --debug \
       --hiera_config /etc/puppet/hiera.yaml \