Update git submodules

* Update docs/submodules/doctor from branch 'master'
  - Merge "Decode received data in byte type to str type"
  - Decode received data in byte type to str type

    json.loads in Python 3.5 doesn't accept a byte-type values so we need to
    decode it. Note that this is specific to Python 3.5; Python 2.7 and 3.6
    accept byte-type values.

    Change-Id: I490f8e0f02a6ce277f86e75b32d1210bfcca8d49
    Signed-off-by: Carlos Goncalves <carlos.goncalves@neclab.eu>

diff --git a/docs/submodules/doctor b/docs/submodules/doctor
index d2b6574..5b1401a 160000 (submodule)
--- a/docs/submodules/doctor
+++ b/docs/submodules/doctor
@@ -1 +1 @@
-Subproject commit d2b6574994e065de13c2d31f9a6d7f27142c0a41
+Subproject commit 5b1401a9194daae197a8f5ae534b9a37dd483eac