Description of problem:
The updating of Grub2 according to /root/anaconda-ks.cfg to use net.ifnames did not take effect for the initial kernel.

Version-Release number of selected component (if applicable):
8.0 Beta and 8.0 Beta Snapshot 2

How reproducible:
Every time

Steps to Reproduce:
1. Boot the VM on top of RHEL 8 host
2. Inside the VM, the 2 VirtIO NICs will have names of ens3 and ens4

Actual results:
The NICs are using the newer "Predictable Network Interface Device Names" which is helpful in physical environments, but less so in virtual environments.

Expected results:
Continue the eth0 style naming as used in RHEL 7.x

Additional info:
This is related to the shift in RHEL 8 to use BLS (Boot Loader Spec).

The following three lines are affected in anaconda-ks.cfg:
# reorder console entries
sed -i 's/console=tty0/console=tty0 console=ttyS0,115200n8/' /boot/grub2/grub.cfg

# add additional flags for the running image
sed -i -e 's/115200n8/115200n8 no_timer_check net.ifnames=0/' /boot/grub2/grub.cfg

# make grub changes persistent
sed -i -e 's/^\{GRUB_CMDLINE_LINUX=.*\}"/\1 no_timer_check net.ifnames=0 console=ttyS0m115200n8"/' /etc/default/grub

It is the first two sed's that are having no effect because they need to edit the /boot/grub2/grubenv file and the kernelopts line to update the "existing" BLS entries. In fact, I *think* a line like:
# adjust existing BLS entries
sed -i -e 's/^\{kernelopts=.*\}/\1 no_timer_check net.ifnames=0 console=ttyS0m115200n8/' /boot/grub2/grubenv

I'll do some testing to see if that last line helps/works for me.