At present the libvirt logging config default to info level.
In past release it was configured to only log warning and above.

As par to OSP 18 all logs on edpm nodes were moved to use journald
to facilitate eaiser log collection for centralised logging and to remove
the need for log rotate.

currently there is no way to conifgre automatic rotation of the journal file via
the new installer, that feature request is tracked by https://issues.redhat.com/browse/RHOSRFE-148

in the absence of this functionality the verboseness of the info level logging of libvirt
contribute to the rate the journal grows at.

this bug aims to reduce the logging to similar level to osp 17 while providing
a limited way to configure the log level going forward.