Update git submodules

* Update docs/submodules/doctor from branch 'master'
  - Merge "fix the pep8 check"
  - fix the pep8 check

    Change-Id: I91b8b6cd07d859a1d1abdc25f015a3c3b2756fab
    Signed-off-by: dongwenjuan <dong.wenjuan@zte.com.cn>

diff --git a/docs/submodules/doctor b/docs/submodules/doctor
index 776ad2a..8b4fa81 160000 (submodule)
--- a/docs/submodules/doctor
+++ b/docs/submodules/doctor
@@ -1 +1 @@
-Subproject commit 776ad2a555b52a6d435f897a11217d669e88bca8
+Subproject commit 8b4fa81e06057e2e0fbda2071c6fbf46cda7a45f