Fixing item loop when undefined variable errors occur because of missing attributes

Fixes a case where the variable 'foo' may exist, but the with_items loop
was used on something like 'foo.results', where 'results' was not a valid
attribute of 'foo'. Prior to this patch, conditionals were not evaluated
until later, meaning there was no opportunity to allow a test to skip the
task or item based on it being undefined.
Fixing bad variable naming choices
Add checks for instances of connecting to invalid region
Add support for new environment variable, RAX_PRIVATE_IP, which will set the ansible_ssh_host value to the private IP of the instances.  Additionally removes redundant parenthesis; documentation redo.