man: correct a factual error in cockpit-browser.1
man: correct a factual error in cockpit-browser.1

We don't use xdg-open, for reasons mentioned in a comment in
cockpit-browser itself.

deryni/cockpit,deryni/cockpit,deryni/cockpit,moraleslazaro/cockpit,cockpit-project/cockpit,moraleslazaro/cockpit,moraleslazaro/cockpit,cockpituous/cockpit,cockpit-project/cockpit,moraleslazaro/cockpit,mvollmer/cockpit,cockpituous/cockpit,moraleslazaro/cockpit,martinpitt/cockpit,cockpit-project/cockpit,garrett/cockpit,martinpitt/cockpit,cockpit-project/cockpit,moraleslazaro/cockpit,moraleslazaro/cockpit,deryni/cockpit,deryni/cockpit,cockpituous/cockpit,martinpitt/cockpit,martinpitt/cockpit,cockpit-project/cockpit,cockpituous/cockpit,deryni/cockpit,cockpituous/cockpit,cockpituous/cockpit,garrett/cockpit,mvollmer/cockpit,mvollmer/cockpit,garrett/cockpit,mvollmer/cockpit,garrett/cockpit,deryni/cockpit,martinpitt/cockpit,mvollmer/cockpit,garrett/cockpit