Installer check for SolusVM

Add a check in the cpanel installer for /usr/local/solusvm

We get on average 2 tickets a week where the cpanel installer has been run on a vps host node. It mainly happens on openvz nodes where the admin thinks they entered into the vps using vzctl enter, however they forgot that part! and destroy there vps system.

This would save a LOT of hassle for us (SolusVM) and vps hosts that fail to do the proper checks.

I know this is all down to user error but a simple check will help solve this problem. We include a check for cpanel in our installer and it's very effective.