[WIP] ONOS-8091 Port python script and utilities to python3

Steps performed so far:
- Updated bash scripts and similar to explicitly invoke python3 (instead of python)
- Updated all python scripts using 2to3

Testing these changes will be a major headache because:
- different scripts are executed in different environments
  (e.g., Jenkins, cell servers, tutorial VMs, etc.)
- we don’t have control on all environments
- some environments we used to control have been dismissed
  (e.g., cell servers)

The approach for now is to focus on the essentials:
- Jenkins jobs for pre-merge and release

Test and fix everything else as the need arises.

Change-Id: I943e214760c9dea9a7ded0d47ef08adbc0ed0bec
diff --git a/tools/test/scenarios/bin/find-link-in-cluster.py b/tools/test/scenarios/bin/find-link-in-cluster.py
index 928531f..1eb6832 100755
--- a/tools/test/scenarios/bin/find-link-in-cluster.py
+++ b/tools/test/scenarios/bin/find-link-in-cluster.py
@@ -1,4 +1,4 @@
-#! /usr/bin/env python
+#! /usr/bin/env python3
 
 import requests
 import sys
@@ -6,7 +6,7 @@
 from requests.auth import HTTPBasicAuth
 
 if len(sys.argv) != 9:
-    print "usage: find-link-in-cluster onos-node name cluster-id expected-length src-device-id src-port dst-device-id dst-port"
+    print("usage: find-link-in-cluster onos-node name cluster-id expected-length src-device-id src-port dst-device-id dst-port")
     sys.exit(1)
 
 node = sys.argv[1]
@@ -24,29 +24,29 @@
                             auth=HTTPBasicAuth('onos', 'rocks'))
 
 if linksRequest.status_code != 200:
-    print linksRequest.text
+    print(linksRequest.text)
     sys.exit(1)
 
 linksJson = linksRequest.json()
 linksLength = len(linksJson["links"])
 
 if  linksLength != length:
-    print "Expected length {} but got {}".format(length, linksLength)
+    print("Expected length {} but got {}".format(length, linksLength))
     sys.exit(1)
 
 for link in linksJson["links"]:
     if srcDeviceId == link["src"]["device"] and srcPort == link["src"]["port"]:
         if dstDeviceId == link["dst"]["device"] and dstPort == link["dst"]["port"]:
-            print "@stc " + name + "SrcDevice=" + link["src"]["device"]
-            print "@stc " + name + "SrcPort=" + link["src"]["port"]
-            print "@stc " + name + "DstDevice=" + link["dst"]["device"]
-            print "@stc " + name + "DstPort=" + link["dst"]["port"]
-            print "@stc " + name + "Type=" + link["type"]
-            print "@stc " + name + "State=" + link["state"]
+            print("@stc " + name + "SrcDevice=" + link["src"]["device"])
+            print("@stc " + name + "SrcPort=" + link["src"]["port"])
+            print("@stc " + name + "DstDevice=" + link["dst"]["device"])
+            print("@stc " + name + "DstPort=" + link["dst"]["port"])
+            print("@stc " + name + "Type=" + link["type"])
+            print("@stc " + name + "State=" + link["state"])
             sys.exit(0)
 
-print "Could not find link from {}:{} to {}:{}"\
-    .format(srcDeviceId, srcPort, dstDeviceId, dstPort)
+print("Could not find link from {}:{} to {}:{}"\
+    .format(srcDeviceId, srcPort, dstDeviceId, dstPort))
 sys.exit(1)