rsync ignore cache folder issues

[grantcodes]

By default all rsync commands ignore all folders named cache, this breaks at least one plugin I know of and I'm sure may cause problems with many more.

I've not submitted a pull request as there are multiple options to fix it:

• I just change it to wp-content/cache which works but not if you don't use the wp-content folder
• You could just remove it as there is the option to add folders to exclude in the config
• Run a function to find the uploads directory and prepend it