Blender Git Loki

Depsgraph: Remove forced dependencies update/evaluation from file open

This was originally done as a fix for T37713, but now this workaround becomes
tricky since we don't know which layers to update scene for. Even more, render
engine is supposed to have own dependency graphs amd those ones do not exist
yet at the file open time.

Keep an eye on T37713, since that's where the original workaround is coming
from.