When upgrading/reconfiguring a rabbit cluster its possible that the nodes
will not return the cluster status for some time, this ps allows us to
cope with this much more gracefully than simply crashing a few times, before
proceeding.
Change-Id: Ibf525df9e3a9362282f70e5dbb136430734181fd
Signed-off-by: Pete Birley <pete@port.direct>