Update instructions for custom image creation. a) Ubuntu xenial should be fine, b) different install of dib

DeployOpenStackHeat.md

@@ -32,18 +32,21 @@ Since generic OpenStack clouds do not support transporting SCTP packets over Flo
 To create an os-*-config ready Ubuntu image you could use the following commands:
 
 ```
+sudo apt-get install pip
+sudo pip installl virtualenv
+virtualenv ~/dib-virtualenv
+. ~/dib-virtualenv/bin/activate
+pip install diskimage-builder
 mkdir custom-image
 cd custom-image
-git clone https://git.openstack.org/openstack/diskimage-builder.git
 git clone https://git.openstack.org/openstack/tripleo-image-elements.git
 git clone https://git.openstack.org/openstack/heat-templates.git
 git clone https://git.openstack.org/openstack/dib-utils.git
-export DIB_RELEASE=trusty
-export PATH="${PWD}/dib-utils/bin:$PATH"
 export ELEMENTS_PATH=tripleo-image-elements/elements:heat-templates/hot/software-config/elements
 diskimage-builder/bin/disk-image-create vm ubuntu os-collect-config os-refresh-config os-apply-config heat-config heat-config-script -o ubuntu-$DIB_RELEASE-os-config.qcow2
 ```
 As a remark (12-12-2016), you can see above that we use trusty (14.04) version of Ubuntu ($DIB_RELEASE). In principle, the heat template works with Ubuntu xenial (16.04), however we have problems connecting UEs to the core when using xenial. So please test with trusty (14.04) version of Ubuntu first.
+Update (4-10-2017) It should be safe to use ubuntu 16.04 xenial as far as read the mailinglist... I updated instructions accordingly. 
 
 **2. Upload your created image to OpenStack**