apps.ipfix: fix bugs in counter initialization
apps.ipfix: fix bugs in counter initialization

eugeneia/snabb,eugeneia/snabb,snabbco/snabb,snabbco/snabb,eugeneia/snabb,eugeneia/snabb,eugeneia/snabb,snabbco/snabb,eugeneia/snabb,snabbco/snabb,snabbco/snabb,snabbco/snabb,snabbco/snabb,snabbco/snabb,eugeneia/snabb,eugeneia/snabb