Python 3 Fix: use proper octal notation

Python3 requires octal notation such as 0o755. Use this as the
compatible syntax instead of the old 0755 syntax for octal.

Change-Id: I0ff2f62ba4b865531adbeba66beec9b7efdc22b4

zuul/launcher/ansiblelaunchserver.py

@@ -797,7 +797,7 @@ class NodeWorker(object):
         remote_path = os.path.join('/tmp', script_fn)
         copy = dict(src=script_path,
                     dest=remote_path,
-                    mode=0555)
+                    mode=0o555)
         task = dict(copy=copy)
         tasks.append(task)
 

zuul/merger/merger.py

@@ -210,7 +210,7 @@ class Merger(object):
         fd.write('#!/bin/bash\n')
         fd.write('ssh -i %s $@\n' % key)
         fd.close()
-        os.chmod(name, 0755)
+        os.chmod(name, 0o755)
 
     def addProject(self, project, url):
         repo = None