Updating dependencies on documentation
Updating dependencies on documentation

Updating the 'Development' documentation:

* cryptography library depends on libffi-devel to successfully build
during pip install.

* python-m2crypto doesn't exist on Fedora packaging system. Replacing
the dnf command with m2crypto and swig.

fedora-infra/fedmsg,fedora-infra/fedmsg,chaiku/fedmsg,fedora-infra/fedmsg,chaiku/fedmsg,chaiku/fedmsg