BUG: fix gradient recusive gaussian in VS debug

This is another case there we are relying on return value optimization
with VectorImages.

Change-Id: I6d8d84939b80a6d82a255b75e105fe6dd0395705
Merge topic 'FixVectorImageGradientRecursiveGaussianRVO'

6a60327 BUG: fix gradient recusive gaussian in VS debug