Add Python 3 support to ovirt4 inventory script. (#57824)

Python 3 only allows strings through the config parser. This is fine for 
the URL, Username, and Password since these values are required. The CA 
File is optional so an empty string is used in leiu of None in the 
config dictionary.

changelogs/fragments/57824-python-3-support-ovirt-dynamic-inv.yml

@@ -0,0 +1,2 @@
+minor_changes:
+  - ovirt4 inventory - Updated the dynamic inventory script for Python 3 support

contrib/inventory/ovirt4.py

@@ -121,7 +121,7 @@ def create_connection():
             'ovirt_url': os.environ.get('OVIRT_URL'),
             'ovirt_username': os.environ.get('OVIRT_USERNAME'),
             'ovirt_password': os.environ.get('OVIRT_PASSWORD'),
-            'ovirt_ca_file': os.environ.get('OVIRT_CAFILE'),
+            'ovirt_ca_file': os.environ.get('OVIRT_CAFILE', ''),
         }
     )
     if not config.has_section('ovirt'):
@@ -133,8 +133,8 @@ def create_connection():
         url=config.get('ovirt', 'ovirt_url'),
         username=config.get('ovirt', 'ovirt_username'),
         password=config.get('ovirt', 'ovirt_password', raw=True),
-        ca_file=config.get('ovirt', 'ovirt_ca_file'),
-        insecure=config.get('ovirt', 'ovirt_ca_file') is None,
+        ca_file=config.get('ovirt', 'ovirt_ca_file') or None,
+        insecure=not config.get('ovirt', 'ovirt_ca_file'),
     )