Fix error response status regression
Fix error response status regression

080a48e introduces a regression where the status field is
missing from the response for non 2xx responses.

Resolves openbmc/openbmc#1246

Change-Id: Idb18b100c9ebb34275b5c24f7609748603749d58
Signed-off-by: Brad Bishop <713d098c0be4c8fd2bf36a94cd08699466677ecd@fuzziesquirrel.com>

openbmc/phosphor-rest-server,openbmc/phosphor-rest-server