Update git submodules

* Update docs/submodules/doctor from branch 'master'
  - Merge "get 'test_case' option form environment variable"
  - get 'test_case' option form environment variable

    Get 'test_case' option form environment variable. If no
    environment variable, use the default value so that we can
    specify the test case in doctor verify job.

    Change-Id: I1bc25d024ca56637d779006d685b57254af355a5
    Signed-off-by: dongwenjuan <dong.wenjuan@zte.com.cn>

diff --git a/docs/submodules/doctor b/docs/submodules/doctor
index bf4c32f..f06386c 160000 (submodule)
--- a/docs/submodules/doctor
+++ b/docs/submodules/doctor
@@ -1 +1 @@
-Subproject commit bf4c32f2729d1014cf572e17a9974587053e3786
+Subproject commit f06386c6b436a0adce7b96c6a1d59b5d02ed31fb