SrmSpaceManager: adapt to UniversalSpringCell instatntiation

Adapts SrmSpaceManager to be instantiated using UniversalSpringCell,
replaces debug with trace,
fixes issues with messageForwarding,
fixed CellPath#insert methods

RELEASE NOTES:

introduced the follwing variables:

spacemanager.service.pnfsmanager.timeout=300
spacemanager.service.pnfsmanager.timeout.unit=SECONDS

spacemanager.service.poolmanager.timeout=300
spacemanager.service.poolmanager.timeout.unit=SECONDS

spacemanager.db.password.file=${srmPasswordFile}

Acked-by: Gerd Behrmann
Require-notes: yes
Require-book: no
Target: trunk
Patch: http://rb.dcache.org/r/5864/