Remove unused function

script/bootstrap

@@ -1,9 +1,7 @@
 #!/usr/bin/env python
 
 import contextlib
-import errno
 import os
-import shutil
 import subprocess
 import sys
 
@@ -24,14 +22,6 @@ def main():
     subprocess.call([sys.executable, 'setup.py', 'build'])
 
 
-def rm_rf(path):
-  try:
-    shutil.rmtree(path)
-  except OSError as e:
-    if e.errno != errno.ENOENT:
-      raise
-
-
 @contextlib.contextmanager
 def scoped_cwd(path):
   cwd = os.getcwd()