one test fails with 1.13rc1

[jschueller]

only one :) can you have a look @adumasphi ?

$ pytest test/
============================= test session starts ==============================
platform linux -- Python 3.6.7, pytest-4.4.2, py-1.8.0, pluggy-0.11.0
rootdir: /home/travis/build/openturns/otpod
collected 358 items / 1 errors / 357 selected
==================================== ERRORS ====================================
______________ ERROR collecting test/test_adaptive_signal_pod.py _______________
test/test_adaptive_signal_pod.py:103: in <module>
    detectionSize3 = POD3.computeDetectionSize(0.9, 0.95)
/home/travis/miniconda/envs/test-environment/lib/python3.6/site-packages/otpod-0.6.1-py3.6.egg/otpod/_decorator.py:53: in f
    return self.mthd(obj, *args, **kwargs)
</home/travis/miniconda/envs/test-environment/lib/python3.6/site-packages/decorator.py:decorator-gen-16>:2: in computeDetectionSize
    ???
/home/travis/miniconda/envs/test-environment/lib/python3.6/site-packages/otpod-0.6.1-py3.6.egg/otpod/_decorator.py:78: in wrapper
    return target(*args, **kwargs)
/home/travis/miniconda/envs/test-environment/lib/python3.6/site-packages/otpod-0.6.1-py3.6.egg/otpod/_kriging_tools.py:71: in computeDetectionSize
    np.max(self._defectSizes))
/home/travis/miniconda/envs/test-environment/lib/python3.6/site-packages/otpod-0.6.1-py3.6.egg/otpod/_pod.py:110: in _computeDetectionSize
    'defect interval, the wanted probability level.')
E   Exception: The POD model does not contain, for the given defect interval, the wanted probability level.