xrootd: Fix regression in GSI support

xrootd4j 1.2.1 requires the unit of the time values in
configuration properties to be defined. Otherwise the
GSI plugin fails to start up.

Target: 2.6
Require-notes: no
Require-book: no
Acked-by: Paul Millar <paul.millar@desy.de>
Patch: http://rb.dcache.org/r/6229/
Merge pull request #289 from gbehrmann/fix/2.6/xrootd-gsi

xrootd: Fix regression in GSI support