Update git submodules

* Update docs/submodules/doctor from branch 'stable/euphrates'
  - fix the way to get log filename

    Change-Id: I9ce494c408c99e1a76a6b485db29a72c3134e487
    Signed-off-by: Ryota MIBU <r-mibu@cq.jp.nec.com>
    (cherry picked from commit 589a60fcd004ee59716273b30cea69aa7b5d102b)

diff --git a/docs/submodules/doctor b/docs/submodules/doctor
index 94d05da..f8d5647 160000 (submodule)
--- a/docs/submodules/doctor
+++ b/docs/submodules/doctor
@@ -1 +1 @@
-Subproject commit 94d05da570a6c2f6be987ef9af8b05c66672cf56
+Subproject commit f8d5647530ead1b88834e941961f5fa939c0f082