app/fib: fix division by zero
app/fib: fix division by zero

This patch fixes the division by 0, which occurs if the number of
routes is less than 10.
Can be triggered by passing -n argument with value < 10:

./dpdk-test-fib -- -n 9
...
Floating point exception (core dumped)

Fixes: 103809d032cd ("app/test-fib: add test application for FIB")
Cc: stable@dpdk.org

Signed-off-by: Vladimir Medvedkin <085731b4c6f11a88aba42f72e5e495cf937bde5a@intel.com>
Acked-by: Kevin Traynor <1f46c93815774a2e602547cf1e37c682d62b566d@redhat.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk