RFR: Adjust reply subjects

[Robin Westberg via github.com]

Hi all,

Please review this small change that adjust the subjects in replies, to improve mail client threading compatibility. 

Best regards,
Robin

----------------

Commits:
 - a87fc352:	Adjust reply subjects

Pull request:
https://git.openjdk.java.net/skara/pull/126

Webrev:
https://webrevs.openjdk.java.net/skara/126/webrev.00

Patch:
https://git.openjdk.java.net/skara/pull/126.diff

Fetch command:
git fetch https://git.openjdk.java.net/skara pull/126/head:pull/126