Corrected some copy paste errors in SLES configuration.

- Corrected vm_name and output_dir regarding version and architecture.
- Made the syntax for vm_name uniform between VirtualBox and VMWare.
Merge pull request #221 from rickard-von-essen/sles_fix

Corrected some copy paste errors in SLES configuration.
Support CentOS 7.0
Merge pull request #237 from andytson/feature/centos-7.0

Support CentOS 7.0