revlogdeltas: always return a delta info object in finddeltainfo...
revlogdeltas: always return a delta info object in finddeltainfo
Previously, the method returned `None` when a full snapshot was needed. The
caller had to determine how to produce one itself.
In practice, building a `_deltainfo` object for a full snapshot is simple. So
we build it at the `finddeltainfo` level and always return a `_deltainfo`
object.
The caller can now simply process the `_deltainfo` return in all cases.