This is also wrong:
http://developer.openstack.org/api-ref/compute/?expanded=create-or-update-metadata-item-detail#create-or-update-metadata-item
/servers/{server_id}/metadata/{key}
This is also wrong:
http:// developer. openstack. org/api- ref/compute/ ?expanded= create- or-update- metadata- item-detail# create- or-update- metadata- item
/servers/ {server_ id}/metadata/ {key}