Use new style string formatting

Author: jaraco

pkg_resources/__init__.py

@@ -1180,17 +1180,17 @@ def extraction_error(self):
             The following error occurred while trying to extract file(s) to the Python egg
             cache:
 
-              %s
+              {old_exc}
 
             The Python egg cache directory is currently set to:
 
-              %s
+              {cache_path}
 
             Perhaps your account does not have write access to this directory?  You can
             change the cache directory by setting the PYTHON_EGG_CACHE environment
             variable to point to an accessible directory.
             """).lstrip()
-        err = ExtractionError(tmpl % (old_exc, cache_path))
+        err = ExtractionError(tmpl.format(**locals()))
         err.manager = self
         err.cache_path = cache_path
         err.original_error = old_exc