My guess is that you have the python-crypto-2.0.1 RPM installed system-wide, and you didn't have gmp-devel installed when you built & installed a later version of PyCrypto, so you're using a newer version of PyCrypto with an older version of _fastmath.
My guess is that you have the python-crypto-2.0.1 RPM installed system-wide, and you didn't have gmp-devel installed when you built & installed a later version of PyCrypto, so you're using a newer version of PyCrypto with an older version of _fastmath.
Is that correct?