Fix ipfw table creation when net.inet.ip.fw.tables_sets = 0 and non zero set
specified on table creation. This fixes following:

sysctl net.inet.ip.fw.tables_sets

net.inet.ip.fw.tables_sets: 0

1. ipfw table all info
2. ipfw set 1 table 1 create type addr
3. ipfw set 1 table 1 create type addr
4. ipfw add 10 set 1 count ip from table\(1\) to any

00010 count ip from table(1) to any

ipfw add 10 set 1 count ip from table\(1\) to any

00010 count ip from table(1) to any

1. ipfw table all info
   • table(1), set(1) --- kindex: 4, type: addr references: 1, valtype: legacy algorithm: addr:radix items: 0, size: 296
   • table(1), set(1) --- kindex: 3, type: addr references: 1, valtype: legacy algorithm: addr:radix items: 0, size: 296
   • table(1), set(1) --- kindex: 2, type: addr references: 0, valtype: legacy algorithm: addr:radix items: 0, size: 296
   • table(1), set(1) --- kindex: 1, type: addr references: 0, valtype: legacy algorithm: addr:radix items: 0, size: 296 #