spacemanager,webadmin,info: Only publish permanent space reservations

Space reservations that are not permanent are usually implicit space
reservations. What the admin and the rest of the world are interested
in are the permanent reservations usually created by the admin.

The patch removes the expiration date and lifetime columns from webadmin
as these are no longer relevant.

Also fixed a type cast bug recently introduced when changing the message
format.

Target: trunk
Require-notes: yes
Require-book: yes
Acked-by: Albert Rossi <arossi@fnal.gov>
Patch: http://rb.dcache.org/r/6478/