Have get_seeds not 500 on an empty seedlist, but respond with a 200 and
an empty list. This will let callers know if there is really no seeds,
or a problem with the service.
Detect if there are truly no seeds available, and if so, continue to
launch with auto_bootstrap forced to false.
Only set replace_* properties if not setting auto_bootstrap to false.
update getseeds unit test to reflect change to behavior
Merge branch 'cluster_bootstrapping' into cluster_bootstrapping_2.0