New csf v5.50

Changes:
– Removed check for Melange on cPanel servers from Server Check Report
– Improvements to the cPanel exim SMTP AUTH login failure regex after changes in cPanel v11.32
– Added exe:/usr/local/cpanel/3rdparty/sbin/mydns to csf.pignore for new installs on cPanel servers
– Additional cmd/pcmd suggestions added to csf.pignore for new installs on cPanel servers (not enabled)