VPP-1508 python tests: unicode

Change unicode references to use text_type

Change-Id: Ia71c16e3235bc509abd3b1c651ae125f892ab108
Signed-off-by: Paul Vinciguerra <pvinci@vinciconsulting.com>
diff --git a/test/vpp_neighbor.py b/test/vpp_neighbor.py
index 7391447..b38aae8 100644
--- a/test/vpp_neighbor.py
+++ b/test/vpp_neighbor.py
@@ -7,10 +7,14 @@
 from ipaddress import ip_address
 from vpp_object import *
 from vpp_papi import mac_pton, VppEnum
+try:
+    text_type = unicode
+except NameError:
+    text_type = str
 
 
 def find_nbr(test, sw_if_index, nbr_addr, is_static=0, mac=None):
-    ip_addr = ip_address(unicode(nbr_addr))
+    ip_addr = ip_address(text_type(nbr_addr))
     e = VppEnum.vl_api_ip_neighbor_flags_t
     nbrs = test.vapi.ip_neighbor_dump(sw_if_index,
                                       is_ipv6=(6 is ip_addr.version))