set 'stopping' during logout action

this flag is used in some cases to determine whether to behave as
though enlightenment is stopping. in the case of logout, we are stopping.

src/bin/e_sys.c

@@ -776,6 +776,7 @@ _e_sys_logout_begin(E_Sys_Action a_after, Eina_Bool raw)
    E_Client *ec;
    E_Obj_Dialog *od;
 
+   stopping = 1;
    /* start logout - at end do the a_after action */
    if (!raw)
      {