security/py-cryptography: Update to 2.9.2 [2]

• Remove patch-PR4855, upstreamed [1]
• Remove asn1crypto, no longer an install_requires (RUN_DEPENDS) [1]
• Add workaround for OpenSSL 1.0.2u/t when building for FreeBSD 11.3-STABLE and 11.4-RELEASE/STABLE. [2]

Changelog:

https://github.com/pyca/cryptography/blob/2.9.2/CHANGELOG.rst

HUGE thank you to Kai for running through extensive QA and producing the
final changeset.

PR: 245929
Submitted by: Daniel <daniel.engberg.lists pyret.net> [1]
Submitted by: kai [2]
MFH: No (backward incompatiblities, substantial dependents count)