DEVEL15-windows-readonly-volume-callbacks-20071109

DEVEL15-windows-readonly-volume-callbacks-20071109

A .readonly volume callback applies to the entire volume.  Track it
in the cm_volume_t cbExpiresRO field and apply it to all cm_scache_t
objects with valid callbacks that are associated with that volume upon
each daemon callback check.  This will prevent premature callback
expiration.

Also, attempt to automatically refresh the callbacks every 30 minutes
by obtaining a callback on the volume root.  This value is configurable
with the "daemonCheckVolCBInterval" registry value.

Change from osi_Time() to time() for expiration values in order to
permit conversion to human readable values in cmdebug.

(cherry picked from commit b43d778e9342dd19c010354cf6db854fdf1f7d22)