minor fix to doc
- added scripted bits that will allow the xvd* => sd* mapping to remain
  consistent on a non-Amazon Linux AMI
spacing and grep-shut-up fixes
yum installs warnings making too much noise (even with e0 and q) so to /dev/null
you go
overall making things quieter > /dev/null 2>&1
noticed that mirrorlist change was being reverted after chroot stage2 so
put that back into cleanup (we *want* that)
removed rpmforge from installation set (causing issues with nagios and
django)