Deploy Templates: Allow old ironic API to return 405

Previous ironic releases without deploy templates support return 405 for
non-GET methods to unsupported endpoints. GET returns 404. In versions
of ironic with API 1.55 support, 404 is returned in all cases.

Change-Id: I501bdcf8a20d9ca14d9ec6adbafda34c35b43a5f
Story: 1722275
Task: 29984
1 file changed