A raw batch request was fully logged which could expose parameters
we don't want logged, like passwords.

Override _repr_iter to use the individual commands to log the
values so that values are properly obscured.

In case of errors log the full value on when the server is in
debug mode.

Reported by Jamison Bennett from Cloudera

Signed-off-by: Rob Crittenden <rcritten@redhat.com>
Reviewed-by: Florence Blanc-Renaud <frenaud@redhat.com>