"leapp preupgrade" fails with "Unable to install RHEL 8 userspace packages." and detailed message "[...] Container system_overlay terminated by signal SEGV."

Issue

• Executing leapp preupgrade on a RHEL7 system fails, the /var/log/leapp/leapp-report.txt file having following content

  Risk Factor: high (error)
  Title: Unable to install RHEL 8 userspace packages.
  Summary: {"details": "Command ['systemd-nspawn', '--register=no', '--quiet', '-D', '/var/lib/leapp/scratch/mounts/root_/system_overlay', ... "stderr": "Host and machine ids are equal (a40addf9f61f4da094d7a803aa010562): refusing to link journals\nModule yaml error: Unexpected key in component\nModule defaults error: Unexpected key in component\nModule yaml error: Unexpected key in component\nModule defaults error: Unexpected key in component\nterminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::uuids::entropy_error> >'\n  what():  open /dev/urandom\nContainer system_overlay terminated by signal SEGV.\n"}
  Key: 5028175de6dcfea0cf809ced42f6e560139a5e8d