test/bpf: fix error message
test/bpf: fix error message

This patch fixed wrong error variable in logging message.

Fixes: 83633ba23076 ("test/bpf: fix few small issues")
Cc: stable@dpdk.org

Signed-off-by: Min Hu (Connor) <f02e10cb0a484c51b0f8634f83fbb4ab9ded1c6a@huawei.com>
Acked-by: Konstantin Ananyev <cbd5212b59ab42a210d72992d23a3aa17cfd3eaf@intel.com>

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