tests: python3 changes for ip6 fib tests

Type: fix
Change-Id: Ie7764fec13cbb83b6899c7c33b7b2f8cc5d40c8a
Signed-off-by: snaramre <snaramre@cisco.com>
diff --git a/test/test_ip6.py b/test/test_ip6.py
index f2c4c00..7c43544 100644
--- a/test/test_ip6.py
+++ b/test/test_ip6.py
@@ -240,7 +240,7 @@
         :param int packet_size: Required packet size.
         :param Scapy pkt: Packet to be modified.
         """
-        dst_if_idx = packet_size / 10 % 2
+        dst_if_idx = int(packet_size / 10 % 2)
         dst_if = self.flows[src_if][dst_if_idx]
         info = self.create_packet_info(src_if, dst_if)
         payload = self.info_to_payload(info)