Link to vmware OVF tool should point to download

Not the documentation
Merge pull request #152 from dhgwilliam/master

Link to vmware OVF tool should point to download
Upgrading the ISO from Centos 6.3 to 6.4.
Reverting everything back to the beginning.

Changed the iso_url for centos to point to the vault.centos.org
so that we can get the binaries for older versions.
Trying an upgrade to see how it fails.
Fixing a stray 'af'.
PE 3.1.2 doesn't exist yet.
Upgrading the ISO from Centos 6.3 to 6.4.
Reverting everything back to the beginning.

Changed the iso_url for centos to point to the vault.centos.org
so that we can get the binaries for older versions.
Merge branch 'bugfix/centosupgrade/klynton' of https://github.com/klynton/puppetlabs-training-bootstrap into bugfix/centosupgrade/klynton

* 'bugfix/centosupgrade/klynton' of https://github.com/klynton/puppetlabs-training-bootstrap:
  PE 3.1.2 doesn't exist yet.
  Fixing a stray 'af'.
  Trying an upgrade to see how it fails.
  Reverting everything back to the beginning.
  Upgrading the ISO from Centos 6.3 to 6.4.
  PE 3.1.2 doesn't exist yet.
  Fixing a stray 'af'.
  Trying an upgrade to see how it fails.
  Reverting everything back to the beginning.
  Upgrading the ISO from Centos 6.3 to 6.4.