bin/remote: don't load repo on root command
bin/remote: don't load repo on root command

Subcommands will demand a repo argument themselves. This allows one to
call `ostree remote` and get the "No subcommand" error rather than the
"Missing --repo" error.

Closes: #1126
Approved by: cgwalters

GNOME/ostree,GNOME/ostree,GNOME/ostree,GNOME/ostree,GNOME/ostree