Update query integration test

[smacker]

Part of the #53

We have one that does hash and then looks for duplicates. We need to update it to test similarity too.

I suggest such a plan:

• Amend current test dataset to include similar file(s)
• Populate DB table hashtables with fixture created using apollo with that dataset
• Use docFreq&params from apollo also
• Run bblfsh server & fe server
• Check query output and make sure both duplicates and similar files appear in the output