Updates based on my initial testing of biFrost

This addes a check of an existing /opt/stack folder. It sets the
execute bit on the env-setup-sh file and updates the README file
based on some findings from my initial tests.

README.rst

@@ -27,7 +27,7 @@ The installation is split in to two parts.
 The first part is a bash script which lays the basic groundwork of installing
 Ansible itself.
 
-Edit ./inventory/group_vars/all.yaml to match your environment.
+Edit ``./inventory/group_vars/all`` to match your environment.
 
 - If MySQL is already installed, update mysql_password to match your local installation.
 - Change network_interface to match the interface that will need to service DHCP requests.

env-setup.sh

@@ -1,12 +1,15 @@
 #!/bin/bash
 
-sudo apt-get -y install git python-pip
-sudo pip install jinja2
+sudo -H apt-get -y install git python-pip
+sudo -H pip install jinja2
 
 u=$(whoami)
 g=$(groups | awk '{print $1}')
 
-mkdir -p /opt/stack || (sudo mkdir -p /opt/stack && sudo chown $u:$g /opt/stack)
+if [ ! -d /opt/stack ]; then
+    mkdir -p /opt/stack || (sudo mkdir -p /opt/stack)
+fi
+sudo -H chown -R $u:$g /opt/stack
 cd /opt/stack
 
 if [ ! -d ansible ]; then