Openflow connetion is released when slave role request with OFPRRFC_UNSUP error returned

When a switch is trying to establish openflow connetcion to a single ODL controller , controller sends slave role request before sending a master role request.

According to the "OpenFlow1.3.4TestSpecification-Basic.pdf"(https://www.opennetworking.org/images/stories/downloads/working-groups/OpenFlow1.3.4TestSpecification-Basic.pdf),clause "440.450 - Role request failed unsupported" defines that an error reply should be returned by the switch with the error code OFPRRFC_UNSUP in this case.

When controller recevices the error with OFPRRFC_UNSUP, it sends slave role request again, and it receives the same error again . The controller retries 42 times and close the connetion.

Thus if the switch obey the rule defined by the test sepecification, it can not connect to an ODL controller.