Steps to Reproduce:
- Define '/' as the machine datastore.
- Use '/var/lib/virt' as the datastore directory.

Expected Results:
- the image is copied to '/var/lib/virt/'

Real Result:
- try to copy the image on '//var/lib/virt'


This is duet the directory is concatenated to the datastore mount point.
Defining the directory as 'var/lib/virt' on the datastore '/' is unusable, many people will try to use '/var/lib/virt'.