openssh_* - catch and report top-level exceptions via `fail_json` (#417)

* ensure exceptions are properly reported

* adding changelog fragment

* applying review suggestions

* typo

* adding back exception msg

changelogs/fragments/417-openssh_modules-fix-exception-reporting.yml

@@ -0,0 +1,4 @@
+---
+bugfixes:
+- openssh_* modules - fix exception handling to report traceback to users for
+  enhanced traceability (https://github.com/ansible-collections/community.crypto/pull/417).

plugins/module_utils/openssh/backends/common.py

@@ -21,9 +21,11 @@ __metaclass__ = type
 import abc
 import os
 import stat
+import traceback
 
 from ansible.module_utils import six
 
+from ansible.module_utils.common.text.converters import to_native
 from ansible_collections.community.crypto.plugins.module_utils.openssh.utils import (
     parse_openssh_version,
 )
@@ -75,7 +77,14 @@ class OpensshModule(object):
         self.check_mode = self.module.check_mode
 
     def execute(self):
+        try:
             self._execute()
+        except Exception as e:
+            self.module.fail_json(
+                msg="unexpected error occurred: %s" % to_native(e),
+                exception=traceback.format_exc(),
+            )
+
         self.module.exit_json(**self.result)
 
     @abc.abstractmethod