dbus: remove useless intf_sys_t.b_unique

(cherry picked from commit b740301ca1847714f7c625b350379c859b99292d)

modules/control/dbus/dbus.c

@@ -179,8 +179,7 @@ static int Open( vlc_object_t *p_this )
     }
 
     char psz_service_name[sizeof(DBUS_MPRIS_BUS_NAME) + 12];
-    p_sys->b_unique = var_CreateGetBool( p_intf, "dbus-unique-service-id" );
-    if( p_sys->b_unique )
+    if( var_InheritBool( p_intf, "dbus-unique-service-id" ) )
         snprintf( psz_service_name, sizeof( psz_service_name ),
                   DBUS_MPRIS_BUS_NAME"-%d", getpid() );
     else

modules/control/dbus/dbus_common.h

@@ -103,7 +103,6 @@ struct intf_sys_t
     input_thread_t *p_input;
     mtime_t         i_last_input_pos; /* Only access it from the input thread */
     mtime_t         i_last_input_pos_event; /* idem */
-    bool            b_unique;
 };
 
 enum