Better lifetime error messages for couch_index.
Better lifetime error messages for couch_index.

Add a log message when the indexer exits as well as format the sig in
log messages has hex.



git-svn-id: c1f8a8ec0b3bb2e99ab3413722f81f687760e79c@1172375 13f79535-47bb-0310-9956-ffa450edef68

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