Added rename of elb_regions to regions

This is a re-posting of the other PR.

Since its better to discuss it here,

@lwade that code path only fires if the:
```
if region_name is not None:
```
Its there to catch the case of specifying a bad region rather than silently falling back to us-east-1. Do you see if this behavior is broken?

@mpdehaan if this PR is fine, i'll open a different one with the indentation fixed