objectstore: set quota for max_bucket into -1 in Grant()
objectstore: set quota for max_bucket into -1 in Grant()

This issue is seen in brownfield cases in which max_bucket
size for the user is set to 0. In rgw, if the max_bucket is 0
then the user can create an unlimited no of buckets.
So for preventing users creating new buckets, set the value to
any negative value

Signed-off-by: Jiffin Tony Thottan <c5f636a65220e122633e16282ed0de93ac96a4fd@redhat.com>

rook/nfs,rook/rook,rook/nfs,rook/rook,rook/rook,rook/rook,rook/rook,rook/nfs