makefs(8) leaves sblock.fs_providersize uninitialized (zero) that can be easily
checked with dumpfs(8). This may lead to other problems, f.e. geom_label kernel
module sanity checks do not like zero fs_old_size value and skips such UFS1
file system while tasting (fs_old_size derives from sblock.fs_providersize).

PR: 203704
Submitted by: eugen@grosbein.net
Reviewed by: marcel