COMP: VS11 error from assigning null to function

explicitly assign a default construction function object, to by pass
issue with VS11 assigning null to tr1::function object.

Change-Id: I47b9c0a0b7c2b75628c63d615596209ca388f34f
Merge topic 'FixFunctionAssignNull' into next

0978b4aa COMP: VS11 error from assigning null to function