Modified path append to work better with Windows, updated use of wait_for_ip calls to work with new params

py-scripts/test_ipv6_connection.py

@@ -7,7 +7,7 @@ if sys.version_info[0] != 3:
     exit(1)
 
 if 'py-json' not in sys.path:
-    sys.path.append('../py-json')
+    sys.path.append(os.path.join(os.path.abspath('..'), 'py-json'))
 import LANforge
 from LANforge.lfcli_base import LFCliBase
 from LANforge import LFUtils