Add location field to virtual guest object

Add location field to the virtual guest object so that cpi can use this field to decide where to create remote iscsi disks

Signed-off-by: Edward Zhang <zhuadl@cn.ibm.com>
Merge pull request #15 from xingzhou/vm_location

Add location field to virtual guest object

Merge this to unblock the work in bosh-softlayer-cpi