track our command string, i.e. everything which cannot be an argument
for a specific command, in resolve_cmd, as we go through the commando
definition there anyway and know if a ARGV element is part of the
command itself or its arguments.
Fixes a problem where a invalid command had all the passed parameter
attached in the resulting USAGE output.
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>