Remove PyOpenSSL backends (except for openssl_pkcs12) (#273)

* Remove Ubuntu 16.04 (Xenial Xerus) from CI.

* Removing PyOpenSSL backend from everywhere but openssl_pkcs12.

* Remove PyOpenSSL support from module_utils that's not needed for openssl_pkcs12.

* Add changelog fragment.

tests/integration/targets/openssl_privatekey_info/tasks/main.yml

@@ -36,42 +36,8 @@
     type: DSA
     size: 1024
 
-- name: Prepare result list
-  set_fact:
-    info_results: {}
-
-- name: Running tests with pyOpenSSL backend
-  include_tasks: impl.yml
-  vars:
-    select_crypto_backend: pyopenssl
-  when: pyopenssl_version.stdout is version('0.15', '>=')
-
-- name: Prepare result list
-  set_fact:
-    pyopenssl_info_results: "{{ info_results }}"
-    info_results: {}
-
 - name: Running tests with cryptography backend
   include_tasks: impl.yml
   vars:
     select_crypto_backend: cryptography
   when: cryptography_version.stdout is version('1.2.3', '>=')
-
-- name: Prepare result list
-  set_fact:
-    cryptography_info_results: "{{ info_results }}"
-
-- block:
-  - name: Dump pyOpenSSL results
-    debug:
-      var: pyopenssl_info_results
-  - name: Dump cryptography results
-    debug:
-      var: cryptography_info_results
-  - name: Compare results
-    assert:
-      that:
-      - '  (pyopenssl_info_results[item] | dict2items | rejectattr("key", "equalto", "deprecations") | list | items2dict)
-        == (cryptography_info_results[item] | dict2items | rejectattr("key", "equalto", "deprecations") | list | items2dict)'
-    loop: "{{ pyopenssl_info_results.keys() | intersect(cryptography_info_results.keys()) | list }}"
-  when: pyopenssl_version.stdout is version('0.15', '>=') and cryptography_version.stdout is version('1.2.3', '>=')