[StGit PATCH] fix export -s

Resolves:
stg export -s `stg top`
Traceback (most recent call last):
  File "/usr/local/lib/python2.5/site-packages/stgit/main.py", line 152, in _main
    ret = command.func(parser, options, args)
  File "/usr/local/lib/python2.5/site-packages/stgit/commands/export.py", line 169, in func
    f = sys.stdout
NameError: global name 'sys' is not defined

Signed-off-by: Dan Williams <redacted>
---
 stgit/commands/export.py |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/stgit/commands/export.py b/stgit/commands/export.py
index dfdcea1..1236b01 100644
--- a/stgit/commands/export.py
+++ b/stgit/commands/export.py

@@ -19,6 +19,7 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 """
 
 import os
+import sys
 from stgit.argparse import opt
 from stgit.commands import common
 from stgit import argparse, git, templates