Passively rate limit repl. message passing
Passively rate limit repl. message passing

Internal replication was causing issues on db5.meritage by trying to
cast messages asynchronously which would end up spawning temporary
proceses to send the message. These processes would then pile up and
eventually overload the node.

This patch uses the new sync option with rexi:cast/4 so that internal
replication will halt while it waits to send a message.

BugzID: 13469

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