Handle delete device requests with no body
Handle delete device requests with no body

We should probably return a 401 rather than a 400 for existing clients that
don't know they have to do the UIA dance to delete a device.

TribeMedia/synapse,TribeMedia/synapse,TribeMedia/synapse,matrix-org/synapse,matrix-org/synapse,TribeMedia/synapse,matrix-org/synapse,matrix-org/synapse,TribeMedia/synapse,matrix-org/synapse,matrix-org/synapse