minor fix about sqlalchemy performance and control access management

tracim/tracim/controllers/admin/user.py

     """
      CRUD Controller allowing to manage groups of a user
     """
-    allow_only = predicates.in_any_group(Group.TIM_ADMIN_GROUPNAME)
+
+    allow_only = predicates.in_group(Group.TIM_ADMIN_GROUPNAME)
 
     _ALLOWED_PROFILE_USER = 'tracim-profile-user'
     _ALLOWED_PROFILE_MANAGER = 'tracim-profile-manager'