Update git submodules

* Update docs/submodules/doctor from branch 'master'
  - Merge "Committer removal (Mario Cho)"
  - Committer removal (Mario Cho)

    https://lists.opnfv.org/pipermail/opnfv-tsc/2018-March/004177.html

    Change-Id: Iebe3b006ac7b921c489dc6819916d250b6695f2f
    Signed-off-by: Ryota MIBU <r-mibu@cq.jp.nec.com>

diff --git a/docs/submodules/doctor b/docs/submodules/doctor
index aee90ea..2889f8c 160000 (submodule)
--- a/docs/submodules/doctor
+++ b/docs/submodules/doctor
@@ -1 +1 @@
-Subproject commit aee90ea41fde62c364d1b194c8e49ff34e6f2cb9
+Subproject commit 2889f8cc9c54b53e2e39a268ff83474ce352239b