builder: Fix handling of VOLUME command where multiple volumes are specified in a space delimited list.
builder: Fix handling of VOLUME command where multiple volumes are
specified in a space delimited list.

Docker-DCO-1.1-Signed-off-by: Erik Hollensbe <github@hollensbe.org> (github: erikh)

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