changegroup: do not delta lfs revisions 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 apply. 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. Differential Revision: https://phab.mercurial-scm.org/D2067