rest-api: coerce nested serializers to simple data types
rest-api: coerce nested serializers to simple data types

This allows zerorpc to understand how to convert our data to a
messagepack

Signed-off-by: Gregory Meno <4c6f7d69a238d85f14b1affaec7960ea26aa1c6d@redhat.com>

r0h4n/ceph-integration