Fix flot xaxis labels

After the flot update the xaxis labels aren't meaningful to humans (in
fact I'm not quite sure what they were showing us). We can explicitly
state the input type as milliseconds and the label render format. Doing
this gives us labels that are meaningful to humans.

Change-Id: I7912a536f3de2756404f8c7e7f31d8bd5890ab22

web/share/elastic-recheck.js

@@ -17,7 +17,9 @@ function update_graph_for_bug(main, bug) {
     if (bug['fails'] > 0) {
         $.plot(div, bug['data'],
                {xaxis: {
-                   mode: "time"
+                   mode: "time",
+                   timeBase: "milliseconds",
+                   timeformat: "%Y/%m/%d"
                }}
               );
     } else {