Return false immediately if $url is empty for common_valid_http_url
Return false immediately if $url is empty for common_valid_http_url

foocorp/gnu-social,chimo/social,foocorp/gnu-social,charnimda/lgbtpzn-social,charnimda/lgbtpzn-social,chimo/social,charnimda/lgbtpzn-social,foocorp/gnu-social,chimo/social