Fix Ruby warnings

Start of fixing warnings provided by Ruby.

Still a **WIP** not ready to merge yet.

Ruby versions:

- [x] 2.1.2
- [ ] 2.1.1
- [ ] 2.1.0
- [ ] 2.0.0
- [x] 1.9.3
- [ ] 1.9.2
- [ ] 1.8.7

- Resolves #1088
@myronmarston I'm stumped on this one. The error only happens on my 1.9.3 RVM setup. I wiped it out, reinstalled 1.9.3-p547, setup a new gemset and did a fresh `bundle --binstubs`.

The warning appears when `--warnings` is set in `.rspec` and I run `bin/rspec`. However, if I use the same Ruby version + gemset and run `ruby -w var_warning.rb` I do not see a similar warning.

Since I didn't see similar warnings on Travis, I'm inclined to revert this one change.