Clarify language around routing services
Clarify language around routing services

See https://github.com/openservicebrokerapi/servicebroker/issues/410

Closes #410

Signed-off-by: Doug Davis <ff3bde741799c0eff815b83a54eda3fc494df54f@us.ibm.com>

servicebroker/servicebroker,openservicebrokerapi/servicebroker,servicebroker/servicebroker,duglin/servicebroker,servicebroker/servicebroker