Reduce retry delay to 10ms, and refactor

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

@@ -1,8 +1,11 @@
-request = require "requestretry"
 Settings = require "settings-sharelatex"
 Errors = require "./Errors"
 Metrics = require "./Metrics"
 logger = require "logger-sharelatex"
+request = (require("requestretry")).defaults({
+	maxAttempts: 2
+	retryDelay: 10
+})
 
 # We have to be quick with HTTP calls because we're holding a lock that
 # expires after 30 seconds. We can't let any errors in the rest of the stack
@@ -28,7 +31,6 @@ module.exports = PersistenceManager =
 				sendImmediately: true
 			jar: false
 			timeout: MAX_HTTP_REQUEST_LENGTH
-			maxAttempts: 2  # for requestretry
 		}, (error, res, body) ->
 			return callback(error) if error?
 			if res.statusCode >= 200 and res.statusCode < 300
@@ -66,7 +68,6 @@ module.exports = PersistenceManager =
 				sendImmediately: true
 			jar: false
 			timeout: MAX_HTTP_REQUEST_LENGTH
-			maxAttempts: 2  # for requestretry
 		}, (error, res, body) ->
 			return callback(error) if error?
 			if res.statusCode >= 200 and res.statusCode < 300

services/document-updater/test/unit/coffee/PersistenceManager/PersistenceManagerTests.coffee

@@ -7,8 +7,10 @@ Errors = require "../../../../app/js/Errors"
 
 describe "PersistenceManager", ->
 	beforeEach ->
+		@request = sinon.stub()
+		@request.defaults = () => @request
 		@PersistenceManager = SandboxedModule.require modulePath, requires:
-			"requestretry": @request = sinon.stub()
+			"requestretry": @request
 			"settings-sharelatex": @Settings = {}
 			"./Metrics": @Metrics =
 				Timer: class Timer
@@ -50,7 +52,6 @@ describe "PersistenceManager", ->
 							sendImmediately: true
 						jar: false
 						timeout: 5000
-						maxAttempts: 2
 					})
 					.should.equal true
 
@@ -130,7 +131,6 @@ describe "PersistenceManager", ->
 							sendImmediately: true
 						jar: false
 						timeout: 5000
-						maxAttempts: 2
 					})
 					.should.equal true