acl: fix test failures caused by remocving legacy ACLs

This commit two test failures:

1. Remove check for "in legacy ACL mode", the actual upgrade will be removed in a following commit.
2. Use the root token in WaitForLeader, because without it the test was
   failing with ACL not found.

agent/consul/acl_endpoint.go

@@ -170,11 +170,6 @@ func (a *ACL) aclPreCheck() error {
 	if !a.srv.config.ACLsEnabled {
 		return acl.ErrDisabled
 	}
-
-	if a.srv.UseLegacyACLs() {
-		return fmt.Errorf("The ACL system is currently in legacy mode.")
-	}
-
 	return nil
 }
 

agent/consul/leader_federation_state_ae_test.go

@@ -383,7 +383,7 @@ func TestLeader_FederationStateAntiEntropyPruning_ACLDeny(t *testing.T) {
 	// Try to join.
 	joinWAN(t, s2, s1)
 	testrpc.WaitForLeader(t, s1.RPC, "dc1")
-	testrpc.WaitForLeader(t, s1.RPC, "dc2")
+	testrpc.WaitForLeader(t, s1.RPC, "dc2", testrpc.WithToken("root"))
 
 	// Create the ACL token.
 	opWriteToken, err := upsertTestTokenWithPolicyRules(client, "root", "dc1", `operator = "write"`)