remoterepo: Handle SHA256 object hash in `ResolveRevision()`
The ResolveRevision()
function of the remoterepo
structure always
parses the object ID returned via the FindCommit()
RPC call as a SHA1
object hash. This of course doesn't work when handling a repository that
uses SHA256 as object hash.
Distinguish the object formats based on the length of the returned object hash. As the RPC call would always return a full object hash anyway this is fine, even though it's a tad ugly.