Description of problem:
When trying to bootstrap a container for CentOS 7, I run into the
following issue.

$ mkdir /var/lib/containers/foo
$ export INSTALLROOT /var/lib/containers/foo
$ yum -y --setopt=reposdir=/home/colin/repos.d --releasever=7
--nogpgcheck --exclude=glibc.i686 --installroot=$INSTALLROOT install
centos-release epel-release yum

(NB /home/colin/repos.d/ just contains a standard CentOS-Base.repo file
from CentOS 7)


<Lots of output, transaction calculations, package downloads etc.>

Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
Traceback (most recent call last):
  File "/usr/bin/yum", line 58, in <module>
    main.user_main(sys.argv[1:], exit_code=True)
  File "/usr/lib/python3.5/site-packages/dnf/yum/main.py", line 86, in
user_main
    errcode = main(args)
  File "/usr/lib/python3.5/site-packages/dnf/yum/main.py", line 44, in main
    return _main(base, args)
  File "/usr/lib/python3.5/site-packages/dnf/yum/main.py", line 82, in _main
    return dnf.cli.main.cli_run(cli, base)
  File "/usr/lib/python3.5/site-packages/dnf/cli/main.py", line 123, in
cli_run
    ret = resolving(cli, base)
  File "/usr/lib/python3.5/site-packages/dnf/cli/main.py", line 150, in
resolving
    base.do_transaction(display=displays)
  File "/usr/lib/python3.5/site-packages/dnf/cli/cli.py", line 222, in
do_transaction
    super(BaseCli, self).do_transaction(display)
  File "/usr/lib/python3.5/site-packages/dnf/base.py", line 662, in
do_transaction
    self._run_transaction(cb=cb)
  File "/usr/lib/python3.5/site-packages/dnf/base.py", line 725, in
_run_transaction
    self._store_config_in_history()
  File "/usr/lib/python3.5/site-packages/dnf/base.py", line 2020, in
_store_config_in_history
    self.history.write_addon_data('config-main', self.conf.dump())
  File "/usr/lib/python3.5/site-packages/dnf/conf/config.py", line 554,
in dump
    if not opt._is_runtimeonly():
AttributeError: 'bool' object has no attribute '_is_runtimeonly'

This works fine when using "dnf" instead of "yum".

Version-Release number of selected component (if applicable):
2.0.0-0.6.rc2.mga6 (= 2.0.0-0.rc2.6.fc26)

How reproducible:
Always

Additional info:

This was reported to me via the mageia-dev mailing list: https://ml.mageia.org/l/arc/dev/2016-12/msg00356.html