Blender Git Loki

LibOverride: Resync: Fix most remaining 'overrides in master collection' issues.

Problem is, when a collection is excluded from the scene, none of its
objects are technically instantiated.

This should not happen when *creating* an override, but can be fairly
common during resync process.

For now, use a lesser precise check in resync case, only relying on
object usercount. This might lead to some objects being left without any
collection in some rare weird case, but this cannot really be avoided
currently.