Node could be assigned to nodegroup which uses another admin/PXE network

Currently it's possible to assign node discovered in non-default PXE network to environment which doesn't use that network:

[root@nailgun ~]# fuel env
id | status | name | mode | release_id | pending_release_id
---|------------|-------------------------|------------|------------|-------------------
1 | deployment | TestMultipleClusterNets | ha_compact | 2 | None
2 | new | DefaultCluster | ha_compact | 2 | None
[root@nailgun ~]# fuel nodegroup
id | cluster | name
---|---------|---------------
1 | 1 | default
2 | 1 | group-custom-1
3 | 2 | default
[root@nailgun ~]# fuel network-group | grep admin
1 | fuelweb_admin | None | 10.109.25.0/24 | 10.109.25.1 | None
10 | fuelweb_admin | None | 10.109.30.0/24 | 10.109.30.2 | 2
[root@nailgun ~]# fuel nodes
id | status | name | cluster | ip | mac | roles | pending_roles | online | group_id
---|-------------|-------------------------|---------|-------------|-------------------|-----------------|---------------|--------|---------
3 | deploying | slave-03_controller | 1 | 10.109.25.4 | 64:fa:14:70:c4:71 | controller | | True | 1
2 | deploying | slave-01_controller | 1 | 10.109.25.3 | 64:e7:60:cb:1e:ec | controller | | True | 1
1 | ready | slave-05_controller | 1 | 10.109.25.5 | 64:e8:08:98:7c:6d | controller | | True | 1
5 | provisioned | slave-02_compute_cinder | 1 | 10.109.30.4 | 64:5e:dd:48:94:70 | cinder, compute | | True | 2
4 | provisioned | slave-04_compute_cinder | 1 | 10.109.30.3 | 64:99:6d:51:44:e6 | cinder, compute | | True | 2
6 | discover | Untitled (5a:e1) | None | 10.109.30.5 | 64:2d:83:ed:5a:e1 | | | True | None
[root@nailgun ~]# fuel --env 2 node set --node 6 --role controller
Nodes [6] with roles ['controller'] were added to environment 2
[root@nailgun ~]# fuel deploy-changes --env 2

Steps to reproduce:

1. Create environment #1
2. Create custom nodegroup for the environment
3. Bootstrap slave node from custom nodegroup
4. Create another environment (with 1 default nodegroup) #2
5. Assign nodes (bootstrapped on step #3) to the environment #2

Expected result: node additioning failed, because the environment doesn't have suitable nodegroup for it

Actual result: node is added to the environment, deployment could be started