buildscripts/requirements.txt specifies cryptography==1.7.2. This fails on openssl >= 1.1.0f with this error: https://github.com/pyca/cryptography/issues/3605

Debian testing presently ships openssl 1.1.0h.

The comment on top of requirements.txt seems to imply that cryptography is only used for jira integration, and grepping the tree doesn't seem to produce any hints of it being used anywhere.

Affects 4.0.0 tag as well as master.