Add fact to get array of nic alias name

This is useful for getting the alias name of
a real network interface name which in turn
will allow users to configure alias name in tht.

Change-Id: I28fae19f8c1c8dacad38d10513330b15bd6cdbe6

lib/facter/nic_alias.rb

@@ -0,0 +1,22 @@
+# Copyright 2018 Red Hat, Inc.
+# All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+Facter.add('nic_alias') do
+  setcode do
+    mapping_report =
+      Facter::Core::Execution.execute('/usr/bin/os-net-config -i')
+    mapping_report.delete("{}' ")
+  end
+end