only archive entries older than the current update

to avoid a stale version of the current update ever being pulled back
from S3

services/track-changes/app/coffee/DocArchiveManager.coffee

@@ -35,6 +35,9 @@ module.exports = DocArchiveManager =
 			if count == 0
 				logger.log {project_id, doc_id}, "document history is empty, not archiving"
 				return callback()
+			else if count == 1
+				logger.log {project_id, doc_id}, "document history only has one entry, not archiving"
+				return callback()
 			else
 				MongoManager.getArchivedDocChanges doc_id, (error, count) ->
 					return callback(error) if error?
@@ -45,7 +48,7 @@ module.exports = DocArchiveManager =
 						return callback(error) if error?
 						MongoManager.markDocHistoryAsArchiveInProgress doc_id, update, (error) ->
 							return callback(error) if error?
-							MongoAWS.archiveDocHistory project_id, doc_id, (error) ->
+							MongoAWS.archiveDocHistory project_id, doc_id, update, (error) ->
 								if error?
 									MongoManager.clearDocHistoryAsArchiveInProgress doc_id, update, (err) ->
 										return callback(err) if err?

services/track-changes/app/coffee/MongoAWS.coffee

@@ -11,7 +11,7 @@ module.exports = MongoAWS =
 	MAX_SIZE:  1024*1024 # almost max size
 	MAX_COUNT: 1024 # almost max count
 
-	archiveDocHistory: (project_id, doc_id, _callback = (error) ->) ->
+	archiveDocHistory: (project_id, doc_id, update, _callback = (error) ->) ->
 
 		callback = (args...) ->
 			_callback(args...)
@@ -19,6 +19,7 @@ module.exports = MongoAWS =
 
 		query = {
 			doc_id: ObjectId(doc_id)
+			v: {$lt: update.v}
 			expiresAt: {$exists : false}
 		}