Bugfix genesis

Applied fix for [issue #129](https://github.com/jdevalk/wordpress-seo/issues/129)

>Broken rel=prev/next on any page with Genesis theme
>
>Wrong contional statement, using OR instead or AND :
>
>There is an error line 691 in frontend/class-frontend.php
>
>replace :
>`if ( is_home() || function_exists( 'genesis' ) )`
>
>by :
>`if ( is_home() && function_exists( 'genesis' ) )`
>
>because the current code (with double pipe) will also exit the pagination script for ANY page if genesis is used !!! And we only want this code to not be executed when it's genesis AND the homepage (current code says "OR")
>
>Cheers,