Merge pull request #549 from ossreleasefeed/show-user-message-when-no…

…-data-750816

show user message on no data fixes 750816

webapp-php/js/socorro/crash_trends.js

@@ -99,7 +99,7 @@ $(function() {
             // remove the loading animation
             $("#loading").remove();
 
-            if(data.nightlyCrashes.length > 0) {
+            if(data.nightlyCrashes) {
                 graph = $.plot("#nightly_crash_trends_graph", data.nightlyCrashes, options);
                 //emty the ul before appending the new dates
                 $("#dates").empty();