Remove the creation on nonce on get acme directory.

According to RFC 8555, the replay nonces are only required in POST
requests. And of course in the new-nonce request.

acme/api/handler.go

@@ -91,8 +91,8 @@ func (h *Handler) Route(r api.Router) {
 	// Standard ACME API
 	r.MethodFunc("GET", getPath(NewNonceLinkType, "{provisionerID}"), h.baseURLFromRequest(h.lookupProvisioner(h.addNonce(h.addDirLink(h.GetNonce)))))
 	r.MethodFunc("HEAD", getPath(NewNonceLinkType, "{provisionerID}"), h.baseURLFromRequest(h.lookupProvisioner(h.addNonce(h.addDirLink(h.GetNonce)))))
-	r.MethodFunc("GET", getPath(DirectoryLinkType, "{provisionerID}"), h.baseURLFromRequest(h.lookupProvisioner(h.addNonce(h.GetDirectory))))
-	r.MethodFunc("HEAD", getPath(DirectoryLinkType, "{provisionerID}"), h.baseURLFromRequest(h.lookupProvisioner(h.addNonce(h.GetDirectory))))
+	r.MethodFunc("GET", getPath(DirectoryLinkType, "{provisionerID}"), h.baseURLFromRequest(h.lookupProvisioner(h.GetDirectory)))
+	r.MethodFunc("HEAD", getPath(DirectoryLinkType, "{provisionerID}"), h.baseURLFromRequest(h.lookupProvisioner(h.GetDirectory)))
 
 	extractPayloadByJWK := func(next nextHTTP) nextHTTP {
 		return h.baseURLFromRequest(h.lookupProvisioner(h.addNonce(h.addDirLink(h.verifyContentType(h.parseJWS(h.validateJWS(h.extractJWK(h.verifyAndExtractJWSPayload(next)))))))))