restore pyboard symlink

This item is a UNIX symbolic link, and (except in the unlikely case
where the symlink is to a pathname that ends with a newline character!)
doesn't contain a newline.

It appears some well-intentioned tool failed to correctly handle this
file, and added a trailing newline as though it was a text file.

Author: jepler

tests/pyboard.py

@@ -1 +1 @@
-../tools/cpboard.py
+../tools/cpboard.py