iptables-restore: Free handle with --test also

iptables-restore: Free handle with --test also

When running 'iptables-restore -t', valgrind reports:

1,496 (160 direct, 1,336 indirect) bytes in 1 blocks are definitely lost in loss record 4 of 4
   at 0x48417E5: malloc (vg_replace_malloc.c:381)
   by 0x4857A46: alloc_handle (libiptc.c:1279)
   by 0x4857A46: iptc_init (libiptc.c:1342)
   by 0x1167CE: create_handle (iptables-restore.c:72)
   by 0x1167CE: ip46tables_restore_main (iptables-restore.c:229)
   by 0x116DAE: iptables_restore_main (iptables-restore.c:388)
   by 0x49A2349: (below main) (in /lib64/libc.so.6)

Free the handle pointer before parsing the next table.

Fixes: 1c9015b2cb483 ("libiptc: remove indirections")
Signed-off-by: Phil Sutter <phil@nwl.cc>