Why does rsyslog delays server reboot on RHEL7?

Issue

• Server reboot on RHEL7 takes more than 5 minutes with lots of below error messages;

Apr 14 13:53:53  rsyslogd: [origin software="rsyslogd" swVersion="7.4.7" x-pid="976" x-info="http://www.rsyslog.com"] exiting on signal 15.
Apr 14 13:55:19  rsyslogd: [origin software="rsyslogd" swVersion="7.4.7" x-pid="999" x-info="http://www.rsyslog.com"] start
Apr 14 13:55:19  rsyslogd-2184: action '*' treated as ':omusrmsg:*' - please change syntax, '*' will not be supported in the future [try http://www.rsyslog.com/e/2184 ]
Apr 14 13:55:19  rsyslogd-2184: action '*' treated as ':omusrmsg:*' - please change syntax, '*' will not be supported in the future [try http://www.rsyslog.com/e/2184 ]