Set publication date for a few old news.

Otherwise, they appear on top of https://tails.boum.org/news/index.it.html
due to the time the corresponding .it.po file was created.

wiki/src/news/bounties_2013_report.mdwn

 [[!meta title="Report on the 2013 Tails bounty program"]]
+[[!meta date="Thu Mar 6 21:36:35 2014"]]
 
 Thanks to the [Knight Foundation](http://www.knightfoundation.org/)
 and to the [Tor project](https://www.torproject.org/), we have

wiki/src/news/report_end_of_2014.mdwn

 [[!meta title="Tails report from August to December 2014"]]
+[[!meta date="Wed Mar 4 14:17:29 2015"]]
 
 As you might have noticed, [[the last monthly
 report|news/report_2014_06-07]] was a long time ago, because the people

wiki/src/news/summit_2013.mdwn

 [[!meta title="Tails 2013 summit report"]]
+[[!meta date="Fri Aug 9 09:12:07 2013"]]
 
 A bunch of people spend a dozen days together in July at the third
 Tails developers yearly summit. This was a great opportunity to have

wiki/src/news/tails-support.mdwn

 [[!meta title="Tails user support mailing list"]]
+[[!meta date="Sat Aug 10 10:42:51 2013"]]
 
 After we closed off our forum in June, the Tails community was left
 without a public user support channel apart from IRC.