Cloned from https://bugzilla.redhat.com/show_bug.cgi?id=2000620

Description of problem:
When provisioning a host with Virtual NIC, the tag is not inherited from the subnet, as it is supposed to do, if we do not specify it.

Version-Release number of selected component (if applicable):

How reproducible:
100%

Steps to Reproduce:
1.In the Satellite web UI, navigate to Hosts > All hosts.
2.Click Edit next to the host you want to edit.
3.On the Interfaces tab, click Add Interface.
4.Select the Virtual NIC check box
5.Do not enter the TAG
6.The template do not render with the VLAN option(vlan=vlan<vlanid>:<interface>)

Actual results:
The tag is not inherited from the subnet. Therefore, the system can't be provisioned.

Expected results:

Additional info:

With tag set explicitly:
---

1. This file was deployed via 'Kickstart default PXEGrub' template

default=0
timeout=10

title Kickstart default PXEGrub
root (nd)
kernel (nd)/../boot/red-hat-enterprise-linux-7-for-scientific-computing-kickstart-x86_64-7-6-76-vmlinuz ks=http://recife.rguerra.lab/unattended/provision network ksdevice=bootif ks.device=bootif kssendmac ks.sendmac inst.ks.sendmac ip=172.20.1.122:::255.255.0.0:essie-elberson.rguerra.lab:eth0.600:none vlan=vlan103:eth0
initrd (nd)/../boot/red-hat-enterprise-linux-7-for-scientific-computing-kickstart-x86_64-7-6-76-initrd.img
---

With no tag set. It is supposed to inherit the tag from the Subnet:
---

1. This file was deployed via 'Kickstart default PXEGrub' template

default=0
timeout=10

title Kickstart default PXEGrub
root (nd)
kernel (nd)/../boot/red-hat-enterprise-linux-7-for-scientific-computing-kickstart-x86_64-7-6-76-vmlinuz ks=http://recife.rguerra.lab/unattended/provision network ksdevice=bootif ks.device=bootif kssendmac ks.sendmac inst.ks.sendmac ip=172.20.1.122:::255.255.0.0:essie-elberson.rguerra.lab:eth0.103:none
initrd (nd)/../boot/red-hat-enterprise-linux-7-for-scientific-computing-kickstart-x86_64-7-6-76-initrd.img
---