Nodepool Install failure

While installing nodepool as instructed in the README.rst
   pip install -U -r requirements.txt

We are seeing the below error message:
  Building lxml version 3.4.4.
  Building without Cython.
  ERROR: /bin/sh: 1: xslt-config: not found

  ** make sure the development packages of libxml2 and
     libxslt are installed **

For more details:
http://paste.openstack.org/show/477592/

Change-Id: I813e5b25194e8b3821eed07ae0494e0930d15827

README.rst

@@ -13,7 +13,8 @@ Install dependencies:
 
     sudo apt-get update
     sudo apt-get -qy install git mysql-server libmysqlclient-dev g++\
-                     python-dev python-pip libffi-dev libssl-dev qemu-utils
+                     python-dev python-pip libffi-dev libssl-dev qemu-utils\
+                     libxml2-dev libxslt1-dev python-lxml
     mkdir src
     cd ~/src
     git clone git://git.openstack.org/openstack-infra/system-config