[Live] fix bug when trying to hydrate nullable Doctrine Entity

[kbond]

Q	A
Bug fix?	yes
New feature?	no
Tickets	n/a
License	MIT

Fixes a regression in 2.1 where a nullable entity is attempted to be loaded from Doctrine. In 2.0, null was dropped from the component data loading the entity wasn't attempted.

[kbond]

I wonder if this change should be in the hydration system itself:

1. If raw prop === the property's default, skip
2. If raw prop === null and the property allows null, skip

[weaverryan]

I wonder if this change should be in the hydration system itself:

Let's keep the behavior simple and predictable (i.e. always run a value through the hydration system) :)

[weaverryan]

Thank you Kevin!