Merge pull request share#242 from share/close-milestone-database

Close milestone database when calling `Backend.close`

Author: ericyhwang

lib/backend.js

@@ -114,7 +114,7 @@ Backend.prototype._shimAfterSubmit = function() {
 };
 
 Backend.prototype.close = function(callback) {
-  var wait = 3;
+  var wait = 4;
   var backend = this;
   function finish(err) {
     if (err) {
@@ -126,6 +126,7 @@ Backend.prototype.close = function(callback) {
   }
   this.pubsub.close(finish);
   this.db.close(finish);
+  this.milestoneDb.close(finish);
   for (var name in this.extraDbs) {
     wait++;
     this.extraDbs[name].close(finish);