COUCHDB-1788 - tolerate undefined source/target when reading _replicator docs
COUCHDB-1788 - tolerate undefined source/target when reading _replicator docs

fkaempfer/couchdb,fkaempfer/couchdb,fkaempfer/couchdb,fkaempfer/couchdb,fkaempfer/couchdb,fkaempfer/couchdb