Fix mypy error.

Author: nascheme

Lib/test/libregrtest/refleak.py

@@ -208,13 +208,13 @@ def check_fd_deltas(deltas):
         return any(deltas)
 
     failed = False
-    for deltas, item_name, checker in [
+    for raw_deltas, item_name, checker in [
         (rc_deltas, 'references', check_rc_deltas),
         (alloc_deltas, 'memory blocks', check_rc_deltas),
         (fd_deltas, 'file descriptors', check_fd_deltas)
     ]:
         # ignore warmup runs; convert to a list for reporting
-        deltas = list(deltas[warmups:])
+        deltas = list(raw_deltas[warmups:])
         failing = checker(deltas)
         suspicious = any(deltas)
         if failing or suspicious: