SystemRandom is not imported correctly

[shelman]

In src/oic/__init__.py, random.SystemRandom is imported via the following code:

try:
    import random.SystemRandom as rnd
except ImportError:
    import random as rnd

In both python2 and python3 this yields an import error and falls back to the random package.

I believe the fix is to change the import to from random import SystemRandom as rnd. The import works locally for me but I am having some trouble with the unit tests and wanted to check in before opening a pull request.

[schlenk]

Thats bad. Yes, PR welcome. That shouldn't break any tests.