Issues with service utils.kde

* general problem running in single-precision FP mode? (`pisa_tests/test_kde_stage.py` fails with [Error: lists contain a non-float value](https://github.com/icecube/kde/blob/master/kde/kde.c))
* but `pisa_tests/test_kde_stage.py` also fails to `assert np.abs(total_no_lin / total_with_lin - 1.0) < 0.05` in double-precision mode