Rename chef-metal to chef-provisioning

Leave references to external services alone until they are updated.
  * ChefSpec tests pass
  * fix kitchen tests by including the required build-essesntials
  cookbook
Only pass along a gem version if it is specified
Update the provisioner requires

The rename(s) in chef-provisioning has had follow on changes in the way
the provisioners are loaded. For those Provisioners that have been
updated to be compliant with the /current/ chef-provisioning structure,
upgrade the require lines.

Also revert the blanket renaming for those provisioners that haven't yet
migrated to the new name/structure
Merge pull request #1 from phatforge/rename_to_chef_provisioning_and_fix

Rename chef-metal to chef-provisioning