Wording of Email sent to new subscriber

I installed the Jetpack subscription module on a client website. This is a professional site, and the client doesn’t like that the email sent to a new subscriber start out with “Howdy”.

I thought I had solved the problem by changing “Howdy” to “Hello” in the following lines in subscriptions.php:

function get_default_settings() {
		return array(
			'invitation'             => __( "Hello.\n\nYou recently followed this blog's posts. This means you will receive each new post by email.\n\nTo activate, click confirm below. If you believe this is an error, ignore this message and we'll never bother you again." , 'jetpack'),
			'comment_follow'  => __( "Hello.\n\nYou recently followed one of my posts. This means you will receive an email when new comments are posted.\n\nTo activate, click confirm below. If you believe this is an error, ignore this message and we'll never bother you again." , 'jetpack')
		);
	}

However, I see from other wording that this file is apparently not being used to generate the email. How can I change this?

http://wordpress.org/extend/plugins/jetpack/