Update git submodules

* Update docs/submodules/doctor from branch 'master'
  - Merge "Add tox and test case to testing document"
  - Add tox and test case to testing document

    Change-Id: I105bd1e92fb70c8dc4a5c239b6574b73bf1b3154
    Signed-off-by: Tomi Juvonen <tomi.juvonen@nokia.com>

diff --git a/docs/submodules/doctor b/docs/submodules/doctor
index 0f607cb..dcbe7bf 160000 (submodule)
--- a/docs/submodules/doctor
+++ b/docs/submodules/doctor
@@ -1 +1 @@
-Subproject commit 0f607cb5efd91ee497346b7f792dfa844d15595c
+Subproject commit dcbe7bf1c26052b0e95d209254e7273aa1eaace1