ssh1: Remove service from dCache

Code will be removed later.

Target: trunk
Require-notes: yes
Require-book: yes
spacemanager: Replace freespaceinbytes with availablespaceinbytes in link group table

Queries and triggers become simpler when we track available space rather
than free space.

On upgrade, the link group table will be updated. The table is small and the
schema change will be almost instantaneous. Note however that should dCache
be downgraded, the schema changes have to rolled back using one of the 'dcache
dabase rollback' commands.

Target: trunk
Require-notes: yes
Require-book: no
spacemanager: Set file to TRANSFERRING on accept file request message

By changing the file entry to TRANSFERRING on the accept
file request rather than response we save:

- A database lookup
- A database update
- A message queueing phase

Target: trunk
Require-notes: yes
Require-book: no