Retrieve SSN from VMware hosts - tested only on VMware ESXi 5.0 & 5.1

Signed-off-by: Jonathan Raffre <jonathan.raffre@nekolover.net>

This pull request implements retrieve of SSN (ServiceTag for HP / Dell / other hardware) for VMware ESXi 5.0 / 5.1.

Thanks to @trogeat for the bug report !