Skopeo crashes on any invalid transport
Skopeo crashes on any invalid transport

We need to verfy that the user entered a valid transport before attempting
to see if the transport exists,  otherwise skopeo segfaults.

Signed-off-by: Daniel J Walsh <7800de746fd39599bc46177380ea6aede7e31e16@redhat.com>

mtrmac/skopeo,mtrmac/skopeo,mtrmac/skopeo