Get rid of backend parameter whenever possible (#883)

* Get rid of backend parameter whenever possible.

* Always auto-detect if backend choices are 'cryptography' and 'auto', resp. always check cryptography version.

* Improve error message.

* Update documentation.

plugins/filter/openssl_csr_info.py

@@ -305,9 +305,7 @@ def openssl_csr_info_filter(data, name_encoding="ignore"):
 
     module = FilterModuleMock({"name_encoding": name_encoding})
     try:
-        return get_csr_info(
-            module, "cryptography", content=to_bytes(data), validate_signature=True
-        )
+        return get_csr_info(module, content=to_bytes(data), validate_signature=True)
     except OpenSSLObjectError as exc:
         raise AnsibleFilterError(str(exc))
 

plugins/filter/openssl_privatekey_info.py

@@ -181,7 +181,6 @@ def openssl_privatekey_info_filter(
     try:
         result = get_privatekey_info(
             module,
-            "cryptography",
             content=to_bytes(data),
             passphrase=passphrase,
             return_private_key_data=return_private_key_data,

plugins/filter/openssl_publickey_info.py

@@ -146,7 +146,7 @@ def openssl_publickey_info_filter(data):
 
     module = FilterModuleMock({})
     try:
-        return get_publickey_info(module, "cryptography", content=to_bytes(data))
+        return get_publickey_info(module, content=to_bytes(data))
     except PublicKeyParseError as exc:
         raise AnsibleFilterError(exc.error_message)
     except OpenSSLObjectError as exc:

plugins/filter/x509_certificate_info.py

@@ -339,7 +339,7 @@ def x509_certificate_info_filter(data, name_encoding="ignore"):
 
     module = FilterModuleMock({"name_encoding": name_encoding})
     try:
-        return get_certificate_info(module, "cryptography", content=to_bytes(data))
+        return get_certificate_info(module, content=to_bytes(data))
     except OpenSSLObjectError as exc:
         raise AnsibleFilterError(str(exc))