This may be related to #338.

I've committed a temporary workaround in 356dacf for this issue, but it should hopefully be temporary!

Many times, when RAModelTest in src/mlpack/tests/krann_search_test.cpp is run, there will be a failure indicating that too many queries have failed the rank approximation guarantee. The output looks a bit like this:

/home/travis/build/mlpack/mlpack/src/mlpack/tests/krann_search_test.cpp(704): fatal error in "RAModelTest": critical check numQueriesFail < maxNumQueriesFail failed [12 >= 12]

But even with the value of 12 there, it should be 5. We should figure out for which tree types this test is failing, and then figure out why it is failing. So a good first step might be to simply print the tree type that is being tested, and see how often it fails with different random seeds; then we can go from there.