Add PRESUBMIT.py to tools/sharding_supervisor/

tools/sharding_supervisor/stdio_buffer.py

Index: tools/sharding_supervisor/stdio_buffer.py
diff --git a/tools/sharding_supervisor/stdio_buffer.py b/tools/sharding_supervisor/stdio_buffer.py
index 50184f48dc3d895b4ef9c5475073cd0ab5371d60..d16220a19812c9e7f38ee5413a53b4c23c3edfd7 100644
--- a/tools/sharding_supervisor/stdio_buffer.py
+++ b/tools/sharding_supervisor/stdio_buffer.py
@@ -4,8 +4,6 @@
 """Syncronized Standard IO Linebuffer implemented with cStringIO."""
 
 import cStringIO
-import os
-import sys
 import threading
 import Queue
 
@@ -20,21 +18,21 @@ class StdioBuffer(object):
     """Helper method for collecting stdio output.  Output is collected until
     a newline is seen, at which point an event is triggered and the line is
     pushed to a buffer as a (stdio, line) tuple."""
-    buffer = cStringIO.StringIO()
+    buf = cStringIO.StringIO()

[csharp, 2013/01/29 01:34:18]

Why buffer to buf?

     pipe_running = True
     while pipe_running:
       char = program_pipe.read(1)
       if not char and self.shard.poll() is not None:
         pipe_running = False
-      buffer.write(char)
+      buf.write(char)
       if char == '\n' or not pipe_running:
-        line = buffer.getvalue()
+        line = buf.getvalue()
         if line:
           self.queue.put((system_pipe, line))
         if not pipe_running:
           self.queue.put((system_pipe, None))
-        buffer.close()
-        buffer = cStringIO.StringIO()
+        buf.close()
+        buf = cStringIO.StringIO()
 
   def handle_pipe(self, system_pipe, program_pipe):
     t = threading.Thread(target=self._pipe_handler, args=[system_pipe,