Clear net.ifnames definition

With RHEL8, net.ifnames is set to 0 in the grub config. This is a change
in the default image which can have user impacts. We want to clear it to
go back to the previously defined behavior in RHEL7.

Change-Id: I621066ea5e0e934668ff4c91e991a95d18e019f7
Closes-Bug: #1841441
(cherry picked from commit 8da8d9a51b)

elements/interface-names/README.md

@@ -0,0 +1,7 @@
+interface-names
+===============
+
+net.ifnames may be 0 in /etc/default/grub which can make generating a
+configuration for the network interfaces difficult. The default in RHEL7
+was to not have this defined. The kernel args can be tuned later in the
+deployment so we want to clean it out if it is defined in grub.

elements/interface-names/install.d/70-clear-net-ifnames

@@ -0,0 +1,10 @@
+#!/bin/bash
+
+set -eux
+set -o pipefail
+
+if [ -f /etc/default/grub ]; then
+    # net.ifacenames is defined and set to 0 starting with RHEL8.
+    # This is a change from RHEL7 which can affect network configurations.
+    sed -i 's/net.ifnames=0//g' /etc/default/grub
+fi

elements/os-net-config/element-deps

@@ -3,3 +3,4 @@ os-refresh-config
 package-installs
 pip-manifest
 openvswitch
+interface-names