heroku/heroku — pull request #981 by ys (2013-12-20 20:55:01+00:00)
Title: Fix ruby2.0 Hash[nil] deprecated warnings in pg.rb

In Ruby 2.0, we get warnings on STDERR. Which will be ArgumentError later.

```
warning: wrong element type nil at 3 (expected array)
warning: ignoring wrong elements is deprecated, remove them explicitly
warning: this causes ArgumentError in the next release
```