Support more than 2 physical interfaces in template

Detailed bug description:
    We enabled two physical interfaces in the template (see attached file), but in face only two last interfaces were enabled

Steps to reproduce:

1. We enabled two physical interfaces in the template. See the part below:
---
         private:
           address_pool: private-pool01
           dhcp: false
           stp: false
           parent_iface:
             phys_dev: !os_env BAREMETAL_PRIVATE_IFACE, vmnet2
             phys_dev: !os_env BAREMETAL_PRIVATE_IFACE2, vmnet3
           params:
             vlan_start: 1000
             vlan_end: 1030

         private2:
           address_pool: private-pool02
           dhcp: false
           stp: false
           parent_iface:
             phys_dev: !os_env BAREMETAL_PRIVATE2_IFACE, vmnet4
             phys_dev: !os_env BAREMETAL_PRIVATE2_IFACE2, vmnet5
           params:
             vlan_start: 1031
             vlan_end: 1060
---

2. But in face only vmnet3 and vmnet5 were added:

---
pivanets@tpi56:~$ brctl show
bridge name bridge id STP enabled interfaces
docker0 8000.56847afe9799 no
fuelbr236 8000.525400c04fe1 yes fuelbr236-nic
fuelbr237 8000.5254004c3a45 yes fuelbr237-nic
fuelbr238 8000.525400801a49 yes fuelbr238-nic
fuelbr239 8000.525400d9c63d yes fuelbr239-nic
fuelbr240 8000.525400bdd043 no fuelbr240-nic
virbr0 8000.525400e28f19 yes virbr0-nic
                            vnet0
virbr1 8000.525400d7a249 yes virbr1-nic
virbr2 8000.5254003ab621 yes virbr2-nic
virbr3 8000.52540084933a yes virbr3-nic
virbr4 8000.005056c00003 no virbr4-nic
                            vmnet3
virbr5 8000.005056c00005 no virbr5-nic
                            vmnet5
---