REGRESSION: Perf dashboard sometimes fails to update zooming level

REGRESSION: Perf dashboard sometimes fails to update zooming level
https://bugs.webkit.org/show_bug.cgi?id=143359

Reviewed by Darin Adler.

The bug was caused by various bugs that ended up in an exception.

* public/v2/app.js:
(App.Pane._handleFetchErrors): Removed superfluous console.log.
(App.Pane.computeStatus): Fixed the bug in r182185 that previousPoint could be null.
(App.PaneController.actions.zoomed): Update the overview when the main chart triggered a zoom.
* public/v2/index.html: Replaced all instances of href="#" by href="javascript:false" to avoid navigating
to # when Ember.js fails to attach event listeners on time.
* public/v2/interactive-chart.js:
(App.InteractiveChartComponent._updateDimensionsIfNeeded): Avoid using a negative width or height when
the containing element's size is 0.
(App.InteractiveChartComponent._updateBrush): Ditto.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@182329 268f45cc-cd09-0410-ab3c-d52691b4dbfc