Blender Git Loki

Fix Cycles still saving render output when error happened

This was fixed ages ago for the interface case but not for the
command line. The thing here is that currently external engines
are relying on reports system to indicate that error happened
so suppressing reports storage in the background mode prevented
render pipeline from detecting errors happened.

This is all weak and i don't like it, but this is better than
delivering black frames from the farm.