Add options argument to _Run() to redirect output.

trychange.py

Index: trychange.py
diff --git a/trychange.py b/trychange.py
index f1ea12ddcc8a47bc45bbdec15746f3f21b1f127c..289b0fe4eac275764663af747dd26bdfbc0f7bad 100755
--- a/trychange.py
+++ b/trychange.py
@@ -433,7 +433,7 @@ def GuessVCS(options, path):
     if e.returncode != errno.ENOENT and e.returncode != 128:
       # ENOENT == 2 = they don't have git installed.
       # 128 = git error code when not in a repo.
-      logging.warn(e.returncode)
+      logging.warn('Unexpected error code: %s' % e.returncode)
       raise
   raise NoTryServerAccess("Could not guess version control system. "
                           "Are you in a working copy directory?")