Use 'v' prefix when specifying Ansible tag

Because the 'v' was missing from the tag label, Ansible installation failed because git could not find it.

While making this change, bumped Ansible version to 1.6.2 :)

Author: smt

boot.sh

@@ -105,7 +105,7 @@ if [ "${should_install_ansible}" == true ]; then
   echo "Ansible installation"
   echo "--------------------"
   sudo easy_install pip
-  sudo CFLAGS="-Wunused-command-line-argument-hard-error-in-future" pip install git+https://github.com/ansible/ansible.git@1.6.1 # We need at least 1.6
+  sudo CFLAGS="-Wunused-command-line-argument-hard-error-in-future" pip install git+https://github.com/ansible/ansible.git@v1.6.2 # We need at least 1.6
   echo ""
   echo ""
 fi