codereview: fix windows

Uploading go files on Windows aborts with gofmt: exceptions.ValueError:
close_fds is not supported on Windows platforms if you redirect stdin/stdout/stderr

R=rsc, mattn, Joe Poirier
CC=golang-dev
https://golang.org/cl/4025046
diff --git a/lib/codereview/codereview.py b/lib/codereview/codereview.py
index 44279d7..8b9dc81 100644
--- a/lib/codereview/codereview.py
+++ b/lib/codereview/codereview.py
@@ -911,7 +911,7 @@
 	if not files:
 		return
 	try:
-		cmd = subprocess.Popen(["gofmt", "-l"] + files, shell=False, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, close_fds=True)
+		cmd = subprocess.Popen(["gofmt", "-l"] + files, shell=False, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, close_fds=sys.platform != "win32")
 		cmd.stdin.close()
 	except:
 		raise util.Abort("gofmt: " + ExceptionDetail())