Fix a naming error for gthread worker

Author: smilerlee

gunicorn/config.py

@@ -106,7 +106,7 @@ def worker_class_str(self):
         # are we using a threaded worker?
         is_sync = uri.endswith('SyncWorker') or uri == 'sync'
         if is_sync and self.threads > 1:
-            return "threads"
+            return "gthread"
         return uri
 
     @property