Fixing opengraph/facebook preview in homepage when using a CDN

Card: https://trello.com/c/VHKSqFrO

It's not working because the image URL is being set to the following: 

```
 <meta property="og:image" content="https://www.edraak.orghttps://d2q9s3qze1y77b.cloudfront.net/static/themes/edraak/images/edraak_logo.54f03d320961.png" />
````