Fixing API tests for travis, hopefully once and for all.

The previously introduced fixture in https://github.com/davidbgk/olympia/commit/ab8a4d6a9d1893d9dd516f57d360502bf2738668#diff-8c7352c8e3b224d65cc58e43d88cc868L1031 should not have affected the number of returned elements given that it's personas. @magopian thoughts?