Add missing guard for leaf data size computation
Add missing guard for leaf data size computation

This is necessary when dealing with pre 1.2 database files.
This could be reproduced by adding a conflict revision to an existing pre 1.2
database.



git-svn-id: c1f8a8ec0b3bb2e99ab3413722f81f687760e79c@1096132 13f79535-47bb-0310-9956-ffa450edef68

apache/couchdb-couch,cloudant/couchdb-couch,alanning/couchdb-couch,fkaempfer/couchdb,apache/couchdb-couch,fkaempfer/couchdb,fkaempfer/couchdb,ngpestelos/couchdb-couch,smithsz/couchdb-couch,cloudant/couchdb-couch,fkaempfer/couchdb,ngpestelos/couchdb-couch,smithsz/couchdb-couch,fkaempfer/couchdb,ngpestelos/couchdb-couch,KlausTrainer/couchdb-couch,cloudant/couchdb-couch,KlausTrainer/couchdb-couch,KlausTrainer/couchdb-couch,apache/couchdb-couch,smithsz/couchdb-couch,fkaempfer/couchdb,alanning/couchdb-couch,alanning/couchdb-couch