Lower local collector log level

The local collector was added as the default but we're not properly
configuring it anywhere so this results in two log messages being
printed. Let's lower one of the messages to info and leave the one about
non-existing directory as a warning to indicate possible
mis-configuration.

Change-Id: I52ead32cce1eaf5f3816507e8e62b270f1a1a1cd
Closes-Bug: #1691003

os_collect_config/local.py

@@ -89,7 +89,7 @@ class Collector(object):
                     basename = os.path.basename(data_file)
                     final_content.append((basename, value))
         if not final_content:
-            logger.warn('No local metadata found (%s)' %
+            logger.info('No local metadata found (%s)' %
                         cfg.CONF.local.path)
 
         # Now sort specifically by C locale