Make gclient pack work again by not prefixing "thread_id>"

gclient.py

Index: gclient.py
===================================================================
--- gclient.py	(revision 134877)
+++ gclient.py	(working copy)
@@ -1571,8 +1571,6 @@
     # Make stdout auto-flush so buildbot doesn't kill us during lengthy
     # operations. Python as a strong tendency to buffer sys.stdout.
     sys.stdout = gclient_utils.MakeFileAutoFlush(sys.stdout)
-    # Make stdout annotated with the thread ids.
-    sys.stdout = gclient_utils.MakeFileAnnotated(sys.stdout)
     # Do it late so all commands are listed.
     # Unused variable 'usage'
     # pylint: disable=W0612
@@ -1586,6 +1584,9 @@
     CMDhelp.usage = '\n\nCommands are:\n' + '\n'.join(cmds)
     parser = Parser()
     if argv:
+      if not argv[0] in ('diff', 'pack'):
+        # Make stdout annotated with the thread ids.
+        sys.stdout = gclient_utils.MakeFileAnnotated(sys.stdout)
       command = Command(argv[0])
       if command:
         # 'fix' the usage and the description now that we know the subcommand.