Add autoraid1 snippet

[xdroop]

This is a snippet I use to detect if the first two hard drives are the same size. If they are, then I set up a RAID-1 on both of them. If they are not, I set up a LVM arrangement. Using this I can use the same kickstart for metal as for VMs, since VMs should almost never have the first two hard drives match.

I've been carting this around since the RHEL4 days -- maybe even the late RHEL3 days -- so I don't remember who should get the original credit for putting it together, but it is probably someone from the ancient origins of the cobbler list.

For some reason I've yet to determine (mostly because I don't do many metal kickstarts any more) it doesn't work with C7. It is untested with RHEL7.