Resolves: rhbz#1369439
Rsyslogd used to read messages from /dev/log together with systemd-journald
which resulted in NetworkManager messages not being passed to syslog due to a
race condition during starting NetworkManager and rsyslogd service. So use
imjournal rsyslog plugin that picks messages from journald instead of using the
/dev/log socket. Same as regular RHEL 7 system.
