* Limit cryptography to < 3.4 for Python < 3.6.
* Work around old pip versions.
* Use constraints file when installing stormssh.
* Work around old pip in RHEL8.2, CentOS 8, Ubuntu 18.04, and OpenSuSE 15
(cherry picked from commit 909ac92fe2)
Co-authored-by: Felix Fontein <felix@fontein.de>
