DW:

DW:
 - Made the store dir selection algorithm configurable via
   'store_dir_select_algorithm'.  There are currently two options:
   'least-load' (storeDirSelectSwapDirLeastLoad(), the default),
   and 'round-robin' (storeDirSelectSwapDirRoundRobin()).
 - Added counter stats to the storeCreate() function to find out
   how often it fails and succeeds.