storage: Omit ":" in tang URL when port is empty.
storage: Omit ":" in tang URL when port is empty.

Otherwise we tell people to curl "localhost:/adv" which wont work.

martinpitt/cockpit,cockpit-project/cockpit,martinpitt/cockpit,garrett/cockpit,cockpit-project/cockpit,martinpitt/cockpit,martinpitt/cockpit,mvollmer/cockpit,martinpitt/cockpit,garrett/cockpit,mvollmer/cockpit,garrett/cockpit,mvollmer/cockpit,cockpit-project/cockpit,garrett/cockpit,mvollmer/cockpit,garrett/cockpit,mvollmer/cockpit,cockpit-project/cockpit,cockpit-project/cockpit