Ensure heartbeats are not skipped
Ensure heartbeats are not skipped

In both the normal and continuous feeds filter functions may return
false. This patch ensures heartbeats are not skipped.

Jira-1289

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