docs: fixes wrong config file reference
The "Troubleshoot the Block Storage configuration in cinder" had
incorrect config filename, this changes it to cinder.conf
Closes-bug:
@@ -21,7 +21,7 @@ tracebacks.
Create commands are listed in the ``cinder-api`` log.
-These entries in the ``cinder.openstack.common.log`` file can be used to
+These entries in the ``cinder.conf`` file can be used to
assist in troubleshooting your Block Storage configuration.
.. code-block:: console
