Add new modprobe-blacklist element.

This element can be used to provide a custom list
of modules via DIB_MODPROBE_BLACKLIST which
will be disabled via modprobe.d/blacklist.conf.

I'm using this to disable network adapters on the
Red Hat TripleO rack where the devices can't be
explicitly disabled via the BIOS.

Change-Id: I8a0a8ee05fa62628434d7f6422577dbf5cdd7a2e

elements/modprobe-blacklist/README.md

@@ -0,0 +1,9 @@
+Blacklist specific modules using modprobe.d/blacklist.conf.
+
+In order to use set DIB_MODPROBE_BLACKLIST to the name of your
+module. To disable multiple modules you can set DIB_MODPROBE_BLACKLIST
+to a list of string separated by spaces.
+
+Example:
+
+  export DIB_MODPROBE_BLACKLIST="igb"

elements/modprobe-blacklist/install.d/80-modprobe-blacklist

@@ -0,0 +1,8 @@
+#!/bin/bash
+set -ex
+
+MODULES_LIST=${DIB_MODPROBE_BLACKLIST:?"Please set DIB_MODPROBE_BLACKLIST."}
+
+for mod_name in $MODULES_LIST; do
+    echo "blacklist $mod_name" >> /etc/modprobe.d/blacklist.conf
+done