srm: Change job ID type from Long to long

A recent patch replaced the canonicalization code such that it no
longer relies on a reference to a particular instance of Long. Thus
we can now use long rather than Long to represent required job IDs.

Target: trunk
Require-notes: no
Require-book: no
Acked-by: Paul Millar <paul.millar@desy.de>
Patch: http://rb.dcache.org/r/5946/