Do not retain module through NotificationListener

Analysis shows we are retaining Module instances via
NotificationListener instances. This turns out to be caused by anonymous
class retaining a reference to AbstractDynamicWrapper, which holds the
module for hashCode/equals purposes.

Change-Id: Iab3c30eb3d03a1387fa1f4b0f3cf16eb348f1117
Signed-off-by: Robert Varga <rovarga@cisco.com>