fix handling of ERROR in response to REMOVE

fix handling of ERROR in response to REMOVE

This allows an error message from a proxied special remote to be
displayed to the client.

In the case where removal from several nodes of a cluster fails,
there can be several errors. What to do? I decided to only show
the first error to the user. Probably in this case the user is not in a
position to do anything about an error message, so best keep it simple.
If the problem with the first node is fixed, they'll see the error from
the next node.