Blender Git Loki

Fix Boundary brush not working when the whole mesh is inside the brush radius

When creating the boundary edit data, the loop can stop because a new
vertex was found further from the boundary than the brush radius or
because all vertices of the mesh were already processed. In this second
case, the max_propagation_step was not set, so the code that laters
calculates the falloff was not working, preventing the mesh from
deforming.

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D9215