For all having trobules with this just run these commands:
cd /
/etc/rc.d/init.d/qmail stop
sed -i 's/-u vpopmail/-u root/g' /var/qmail/supervise/submission/run
sed -i 's/-g vpopmail/-g root/g' /var/qmail/supervise/submission/run
sed -i 's/-u vpopmail/-u root/g' /var/qmail/supervise/smtp/run
sed -i 's/-g vpopmail/-g root/g' /var/qmail/supervise/smtp/run
sed -i 's/-u vpopmail/-u admin/g' /var/qmail/supervise/spamd/run
/etc/rc.d/init.d/qmail start
And all will work
/script/cleanup might be needed too because of maildrop bug - just wait till yum info httpd then you can kill this process. Make sure to backup your /etc/php-fpm.d, /home/apache and /home/nginx folders because they will be removed.
Make sure all is working:
qmailctl stat
If yes no need to reboot.