Update git submodules

* Update plugins/singleusergroup from branch 'master'
  - Actually remove Buck based build
    
    Accidentaly, the wrong file was removed. It was supposed to remove BUCK
    and not BUILD.
    
    This partially reverts commit 6800d41177013999c7259b387314d812cb51bcce.
    
    Change-Id: Ia131c160a614b7d6dae242def0ace2203dde1230
    

plugins/singleusergroup

diff --git a/plugins/singleusergroup b/plugins/singleusergroup
index 6800d41..69a0553 160000
--- a/plugins/singleusergroup
+++ b/plugins/singleusergroup
@@ -1 +1 @@
-Subproject commit 6800d41177013999c7259b387314d812cb51bcce
+Subproject commit 69a0553ee0608f3057ec4e3dd17eb93401203181