sync: Fix syntax error on Python 2.4

Change-Id: I371d032d5a1ddde137721cbe2b24bfa38f20aaaa
Signed-off-by: Shawn O. Pearce <sop@google.com>

subcmds/sync.py

@@ -163,6 +163,7 @@ later is required to fix a server side protocol bug.
       # - We always set err_event in the case of an exception.
       # - We always make sure we call sem.release().
       # - We always make sure we unlock the lock if we locked it.
+      try:
         try:
           success = project.Sync_NetworkHalf(quiet=opt.quiet)