Fix for the case where plugins aren't loaded on old RHEL systems

lib/ansible/modules/packaging/os/yum.py

@@ -972,7 +972,12 @@ def main():
         # loaded and plugins are discovered
         my.conf
         repoquery = None
-        if 'rhnplugin' in my.plugins._plugins:
+        try:
+            yum_plugins = my.plugins._plugins
+        except AttributeError:
+            pass
+        else:
+            if 'rhnplugin' in yum_plugins:
                 repoquerybin = ensure_yum_utils(module)
                 if repoquerybin:
                     repoquery = [repoquerybin, '--show-duplicates', '--plugins', '--quiet']