Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "[doctor] fix node-label setting"
  - [doctor] fix node-label setting

    Current doctor verify jobs need to be run on relevant pods which are
    specified by slave-label. But, after multijob introduced, the parameter
    is not passed to children jobs. Also, 'phase' of project is misleading,
    as it isn't multijob's phase.

    This patch makes sure each doctor job run on correct pod by updating
    node label rule for doctor pod to 'doctor-{installer}-{arch}'.

    This patch also merges doctor slave parameter definitions into one,
    and deletes unnecessary setting where default are set.

    Change-Id: Ic9bf218ae7fb4f9866b510efd1e0ccd19277b78e
    Signed-off-by: Ryota MIBU <r-mibu@cq.jp.nec.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 5f73ab5..f6b7459 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 5f73ab5e7935451dba7fc27c9026136cdd835605
+Subproject commit f6b74591649003b937b6038d109a3019cac2f9aa