swift: we must use the number of default sack
swift: we must use the number of default sack

We currently set the number of sack already configured instead of the
asked number. Making upgrade fail when the number of sack is not yet
set.

This change fixes that.

gnocchixyz/gnocchi,leandroreox/gnocchi,leandroreox/gnocchi,gnocchixyz/gnocchi,sileht/gnocchi,sileht/gnocchi