s3select:test_generate_projection wrong index of split

[alphaprinz]

In s3select:test_generate_projection test, the response is split, but the wrong index is taken.
This fix can make the test pass:

orig: assert( abs(float(res.split("\n")[1]) - eval(e)) < epsilon )
fix: assert( abs(float(res.split("\n")[0]) - eval(e)) < epsilon )