Fix undefined name "sys"

Same as #299 (bca0eff81a1c5ef160d9858b8e89b1c919b71c1f), but an earlier
commit needed to be rebased.
diff --git a/devtools/fixeol.py b/devtools/fixeol.py
index 054eb9b..b55e146 100644
--- a/devtools/fixeol.py
+++ b/devtools/fixeol.py
@@ -5,6 +5,7 @@
 
 from __future__ import print_function
 import os.path
+import sys
 
 def fix_source_eol(path, is_dry_run = True, verbose = True, eol = '\n'):
     """Makes sure that all sources have the specified eol sequence (default: unix)."""