Update to 2.3
    
    - New upstream release pycrypto 2.3:
      - Fix NameError when attempting to use deprecated getRandomNumber() function
      - _slowmath: Compute RSA u parameter when it's not given to RSA.construct;
        this makes _slowmath behave the same as _fastmath in this regard
      - Make RSA.generate raise a more user-friendly exception message when the
        user tries to generate a bogus-length key
    - Add -c option to %setup because upstream tarball has dropped the top-level
      directory
    - Run benchmark as part of %check if we have python 2.4 or later
    - BR: python2-devel rather than just python-devel
    - Add patch to make sure we can find libgmp in 64-bit multilib environments