It's a bad practice to use version control for site deployments/updates. Consider using a deployment tool which uses SVN like Capistrano. Start Googling around and you'll articles like [this one](http://theme.fm/2011/08/tutorial-deploying-wordpress-with-capistrano-2082/).

Advantages of using Capistrano

1. Easy deployments (more error proof than vcs deployments)
2. Easy rollbacks (maintains previous versions of your codebase)
3. More secure (doesn't expose a .git directory for example)
4. Zero downtime (doesn't over switch until all the files have been downloaded)

Mark Jaquith, one of WordPress's lead developers talks about this in a [WordCamp](https://wordpress.tv/2013/10/14/deploying-wordpress-with-wpstack/).