Test for same tag, different values

I thought I might be able to hack around the lack of a logical OR operator for tags [like cucumber](https://github.com/cucumber/cucumber/wiki/Tags#logically-anding-and-oring-tags) by using DeMorgan's law, but I found that doesn't work for different values of the same tag.

In the test I added, I was hoping to get something like:
`exclude {:type=>"special", :type=>"custom"}`
but the tags overwrite each other, so I just get
`exclude {:type=>"custom"}`

Tests fails for both rspec2 and rspec3.