Boto blindly assumes the us-east-1 region if you don't hardcode a
region in it's config, so you could end up attempting to modify ELB's
in one region from a totally different region.  If a region isn't
specified then default to the region that the module is being run
within rather than the default us-east-1 region since it's a pretty
safe assumption that you intend to work on the ELB's within your
current region.

Also throw an error if a specified ELB instance doesn't exist.  The old
behavior would be to silently succeed with changed=false, so if you had
so much as a typo in the name of your ELB (or were in the wrong region
like my initial testing) you wouldn't get a clear indication that a
problem had occurred.

Revert "Added an elb_region parameter for interacting with the ec2 elastic load balancer to work with regions other than us-east-1"

This reverts commit 1264a5b4.

Added an elb_region parameter for interacting with the ec2 elastic load balancer to work with regions other than us-east-1

This module handles AWS EC2 ELB registration.

* De-registration requires the instance id which can be looked up using
  the ec2_facts module.
* Registration requires both the instance id and the elbs that the
  instance belongs to.

De-registration will return an ec2_elb fact that can be used for
registration in post_tasks.