There is no way to distinguish whether a delta base is LFS or non-LFS.
If the delta is against LFS rawtext, and the client trying to apply it has
the base revision stored as fulltext, the delta (aka. bundle) will fail to
This patch forbids using delta for LFS revisions in changegroup so bad
deltas won't be transmitted.
Note: this does not solve the problem entirely. It solves LFS delta applying
to non-LFS base. But the other direction: non-LFS delta applying to LFS base
is not solved yet.