bisect-kit: fix some pytype warnings

BUG=None
TEST=unit test

Change-Id: Ic0a5efd5609a9cdc9b12724d93fac5e9c975e6ff
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/bisect-kit/+/2653433
Tested-by: Kuang-che Wu <kcwu@chromium.org>
Auto-Submit: Kuang-che Wu <kcwu@chromium.org>
Commit-Queue: Zheng-Jie Chang <zjchang@chromium.org>
Reviewed-by: Zheng-Jie Chang <zjchang@chromium.org>
diff --git a/bisect_kit/android_util.py b/bisect_kit/android_util.py
index 6189dbd..9f7a5f5 100644
--- a/bisect_kit/android_util.py
+++ b/bisect_kit/android_util.py
@@ -68,7 +68,7 @@
   logger.warning('fetch_android_build_data need to be hooked')
   try:
     return urllib.request.urlopen(url).read().decode('utf8')
-  except urllib.request.URLError as e:
+  except urllib.error.URLError as e:
     logger.exception('failed to fetch "%s"', url)
     raise errors.ExternalError(str(e))