Fix external volume error to pass validation.
Fix external volume error to pass validation.

Signed-off-by: Daniel Nephin <6347c07ae509164cffebfb1e2a0d6ed64958db19@docker.com>

riyazdf/cli,Zebrilee/cli,ashfall/cli,Zebrilee/cli,dnephin/cli,riyazdf/cli,redpanda/cli,dnephin/cli,redpanda/cli,cpuguy83/cli,ashfall/cli,thaJeztah/cli,docker/cli,e11137/cli,allencloud/cli,gdevillele/cli,cpuguy83/cli,docker/cli,thaJeztah/cli,e11137/cli,allencloud/cli