Update git submodules

* Update plugins/singleusergroup from branch 'master'
  - Remove unused import
    
    Change-Id: I6dcaa3e2dab07d001854ba4fd36c0d624b285c4a
    
diff --git a/plugins/singleusergroup b/plugins/singleusergroup
index 262ba95..73cfc73 160000
--- a/plugins/singleusergroup
+++ b/plugins/singleusergroup
@@ -1 +1 @@
-Subproject commit 262ba951fbb24af6094be40637fbd261d5e08218
+Subproject commit 73cfc73077d249a5d92ae3d31f1949b816bd98c3