Fix lint (#8246)

JukkaL · web-flow · commit 9756b59a4187 · 2020-01-06T13:12:50.000Z
IOError is an alias to OSError in Python 3.3+.
diff --git a/mypy/util.py b/mypy/util.py
@@ -142,7 +142,7 @@ def read_py_file(path: str, read: Callable[[str], bytes],
     """
     try:
         source = read(path)
-    except (IOError, OSError):
+    except OSError:
         return None
     else:
         try:
