Fix compactor crash when .compact file is missing header
Fix compactor crash when .compact file is missing header

Users affected by COUCHDB-968 can take advantage of this patch to
force a compaction in retry mode and thus remove the duplicates.
Simply create an empty dbname.couch.compact file in the database_dir
before triggering the compaction for dbname.

git-svn-id: c1f8a8ec0b3bb2e99ab3413722f81f687760e79c@1043540 13f79535-47bb-0310-9956-ffa450edef68

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