[fix] timeout and response parsing order

searx/search.py

     def process_callback(response, **kwargs):
         response.search_params = params
 
+        timeout_overhead = 0.2  # seconds
+        search_duration = time() - params['started']
+        timeout_limit = engines[engine_name].timeout + timeout_overhead
+        if search_duration > timeout_limit:
+            engines[engine_name].stats['page_load_time'] += timeout_limit
+            engines[engine_name].stats['errors'] += 1
+            return
+
         # callback
         try:
             search_results = callback(response)
                 engine_name, str(e))
             return
 
-        timeout_overhead = 0.2  # seconds
-        search_duration = time() - params['started']
-        timeout_limit = engines[engine_name].timeout + timeout_overhead
-        if search_duration > timeout_limit:
-            engines[engine_name].stats['page_load_time'] += timeout_limit
-            engines[engine_name].stats['errors'] += 1
-            return
-
         # add results
         for result in search_results:
             result['engine'] = engine_name