Remove powermta check (not enough customers use this)

Fix get_environment subroutine to check for /var/cpanel/envtype and fall back to
running /usr/local/cpanel/bin/envtype if it doesn't exist.  Also if that command fails
warn user with unknown envtype error.

Fix memory limit check (CL) to use open instead of cat (system) command.

Fix check for frontpage RPM's to check @rpm_list instead of running the RPM command again.