stop OpRangeNotAvailable errors going to sentry

services/document-updater/app/coffee/DispatchManager.coffee

@@ -2,6 +2,7 @@ Settings = require('settings-sharelatex')
 logger = require('logger-sharelatex')
 Keys = require('./UpdateKeys')
 redis = require("redis-sharelatex")
+Errors = require("./Errors")
 
 UpdateManager = require('./UpdateManager')
 Metrics = require('./Metrics')
@@ -23,7 +24,9 @@ module.exports = DispatchManager =
 					# Dispatch this in the background
 					backgroundTask = (cb) ->
 						UpdateManager.processOutstandingUpdatesWithLock project_id, doc_id, (error) ->
-							logger.error err: error, project_id: project_id, doc_id: doc_id, "error processing update" if error?
+							# log everything except OpRangeNotAvailable errors, these are normal
+							if error? and not (error instanceof Errors.OpRangeNotAvailableError)
+								logger.error err: error, project_id: project_id, doc_id: doc_id, "error processing update"
 							cb()
 					RateLimiter.run backgroundTask, callback