Turns out that 'query-nodes' is not what we want and the
'query-blockstats' command was in fact buggy. Revert the new field since
it's not needed.

This reverts commit 50edca13.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>