connections.cgi: Fix Expires time Heading in Connections cgi page

connections.cgi: Fix Expires time Heading in Connections cgi page

- The Expires time heading for the Connections WUI page has seconds listed. However the
   code is converting the seconds to hours:minutes:seconds.
- This patch is changing the heading to H:M:S in English and the equivalent in the other
   languages. I have basewd this on the initial letter for Hours, Minutes & Seconds in
   each of the languages.

Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
Reviewed-by: Peter Müller <peter.mueller@ipfire.org>