Allow fd:// like unix:// and tcp://
Allow fd:// like unix:// and tcp://

Somthing like 20605eb310f0b57bd06eea80ec63c5022fc83bde

Docker-DCO-1.1-Signed-off-by: Brandon Philips <brandon.philips@coreos.com> (github: philips)

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