Update extension.py to clean request.path before logging it (#351)

* Update extension.py to use string format specifier for cleaning request.path

Author: aneshujevic

flask_cors/extension.py

@@ -193,7 +193,7 @@ def cors_after_request(resp):
         normalized_path = unquote_plus(request.path)
         for res_regex, res_options in resources:
             if try_match(normalized_path, res_regex):
-                LOG.debug("Request to '%s' matches CORS resource '%s'. Using options: %s",
+                LOG.debug("Request to '%r' matches CORS resource '%s'. Using options: %s",
                       request.path, get_regexp_pattern(res_regex), res_options)
                 set_cors_headers(resp, res_options)
                 break