Move empty local repo logic for pull into findincoming
This fixes a silly attempt to pull a changegroup from an empty repo.
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 1 changesets, 1 total revisions