Blender Git Loki

OpenSubdiv: Use explicit storage for edge sharpness

Similar to previous change in vertex sharpness, explicitly store value
provided by the converter.

Allows to avoid rather fragile check for boundary edges.

Also allows to avoid need in constructing edge map. This lowers memory
footprint of the comparison process and avoids memory allocations
during the comparison (which is an extra benefit from the performance
point of view).