Update git submodules

* Update docs/submodules/so.git from branch 'master'
  to 2109b159bb28fc8eff6613b227fe7e5d5d8ae915
  - Update NSI slection process
    
    Issue-ID: SO-2949
    
    Signed-off-by: zm330 <zhangminyj@chinamobile.com>
    Change-Id: Ibb13fb6d146d5ef9dbe702c23294653276204f7a
    
diff --git a/docs/submodules/so.git b/docs/submodules/so.git
index d78c7ad..2109b15 160000
--- a/docs/submodules/so.git
+++ b/docs/submodules/so.git
@@ -1 +1 @@
-Subproject commit d78c7ad1413811e67a4fa0a2bdf8a53a860a4252
+Subproject commit 2109b159bb28fc8eff6613b227fe7e5d5d8ae915