ignore missing files in chmod() that can happen for '*.pyc' and '*.pyo'.

src/zc/buildout/easy_install.py

@@ -2081,7 +2081,7 @@ def _final_version(parsed_version):
     return True
 
 def chmod(path):
-    if os.path.islink(path):
+    if os.path.islink(path) or not os.path.exists(path):
         return
     # give the same permission but write as owner to group and other.
     current_perm = os.stat(path).st_mode & \