The test wasn't working when postgres used the English dictionary
because in English the word "what" was ignored (or, at least, not given
enough relevance) while searching. When we wrote the test, it passed
because back then we always used the Spanish dictionary. However, when
we switched to a dictionary based on the default locale (in commit
d99875cd), we had to force this test to keep using the Spanish
dictionary.
Using the Spanish dictionary in a test where all texts are in English is
strange to say the least ;). So here we're making the test a bit easier
to understand.
Since now we're only using the `:spanish_search` tag in one test, I've
decided to remove it and simply add it to that test's setup.
