tests: Add missing socket imports in tests

Type: fix
Change-Id: I646f96517d3bda5c0f5644e6bb89ade7818fc466
Signed-off-by: Tom Jones <thj@freebsd.org>

test/test_ikev2.py

@@ -1,4 +1,5 @@
 import os
+import socket
 import time
 from socket import inet_pton
 from cryptography import x509

test/vpp_ipsec.py

@@ -1,3 +1,5 @@
+import socket
+
 from vpp_object import VppObject
 from ipaddress import ip_address
 from vpp_papi import VppEnum

test/vpp_papi_provider.py

@@ -6,6 +6,7 @@
 #
 
 import os
+import socket
 import time
 import queue
 from six import moves, iteritems