2D Rigidbody type changing from Kinematic->Dynamic at runtime doesn't work

[miwarnec]

I create a 2D KinematicPosition Rigidbody.
Change it to Dynamic 3 seconds later.
Apply a velocity in every update afterwards.

The Rigidbody never moves again after it was kinematic once.

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Same happens if I create a Dynamic Rigidbody.
Change to Kinematic.
Change back to Dynamic 3 seconds later.
Applying velocity never movies it again.

[MaxCWhitehead]

This may have been fixed in #599