Ensure that current uses of BaseException are required

* In some cases, it appears that Exception should have been used instead
  as there's no need to catch sys.exit KeyboardInterrupt and similar.
* In a few cases, it appears that BaseException is used because
  a library we depend on calls sys.exit() contrary to good coding
  design.  Comment those so that we know that those have been audited
  and found to be correct and change to use (Exception, SystemExit)
  instead.

test/sanity/import/importer.py

@@ -99,6 +99,8 @@ def test_python_module(path, base_dir, messages, ansible_module):
     except ImporterAnsibleModuleException:
         # module instantiated AnsibleModule without raising an exception
         pass
+    # We truly want to catch anything the plugin might do here, including call sys.exit() so we
+    # catch BaseException
     except BaseException as ex:  # pylint: disable=locally-disabled, broad-except
         capture_report(path, capture, messages)
 

test/units/modules/network/cloudvision/test_cv_server_provision.py

@@ -23,7 +23,7 @@ sys.modules['cvprac.cvp_client_errors'] = Mock()
 from ansible.modules.network.cloudvision import cv_server_provision
 
 
-class MockException(BaseException):
+class MockException(Exception):
     pass