Bump MODULE_VERSION to 5.2.1

Change-Id: I111d9902592255ee41a665b5b34e14f4885e9136
Reviewed-by: Matti Paaso <matti.paaso@digia.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>

.qmake.conf

 load(qt_build_config)
 
-MODULE_VERSION = 5.2.0
+MODULE_VERSION = 5.2.1