This fix resolves an issue on EL6 systems where there may be multiple versions
of pycrypto installed. EPEL provides both `python-crypto` and
`python-crypto2.6`. These packages are co-installable. However, modules
importing the `Crypto` library must specify which version to use, otherwise the
default will be used.
This change follows the same pattern established in `bin/ansible` for
specifying python library requirements.