Fix chattr +C of VM images.

Turns out you have to chattr before you create. Weird but true.

Change-Id: Ib1483c3ec8400aa363f5e964c32cba100ed40e7e
Allow more time for overcloud bring-up.

50% increase in nodes adds 50% to the time, more or less (at the
moment anyhow).

Change-Id: I05166bedc9f0d88935026a3ab36647fa0acfb00c