Revise use of the vinum_conf variables drives_used, subdisks_used, plexes_used and volumes_used.  Now these fields are only informative, and the <object>_allocated count is used for searches, etc.  This also required checking the object state before doing things with the presumed object.
Revise use of the vinum_conf variables drives_used, subdisks_used,
plexes_used and volumes_used.  Now these fields are only informative,
and the <object>_allocated count is used for searches, etc.  This also
required checking the object state before doing things with the
presumed object.

Problems-reported-by: Kiril Mitev <kiril@ideaglobal.com>

vinum_scandisk: increment drive use count when we find a good one.

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase