Find job for clearing logs only if it's already in store

Otherwise we make ajax request every time job is created.

assets/scripts/app/pusher.coffee

@@ -41,8 +41,8 @@ $.extend Travis.Pusher.prototype,
     # TODO remove job:requeued, once sf-restart-event has been merged
     # TODO this also needs to clear logs on build:created if matrix jobs are already loaded
     if event == 'job:created' || event == 'job:requeued'
-      job = Travis.Job.find(data.job.id)
-      job.clearLog() if job
+      if Travis.store.isInStore(Travis.Job, data.job.id)
+        Travis.Job.find(data.job.id).clearLog()
 
     Ember.run.next ->
       Travis.app.store.receive(event, data)

assets/scripts/app/store.coffee

@@ -67,6 +67,9 @@ Travis.Store = DS.Store.extend
 
       { id: id, clientId: clientId }
 
+  isInStore: (type, id) ->
+    !!@typeMapFor(type).idToCid[id]
+
   receive: (event, data) ->
     [name, type] = event.split(':')