Raise minimum cryptography version to 2.2.1, drop python 2.6#742

Merged

alex merged 1 commit intopyca:masterfrom jlaine:cryptography-2.2

Mar 21, 2018

+13-47

Commits on Mar 21, 2018

Raise minimum cryptography version to 2.2.1, drop python 2.6
jlaine
committed