When invoking Documentation/replace_macros.py, bazel removes environment
using 'env -e', the python script includes '#!env python' shebang, the
result is python not found.
Alignment with js.bzl resolves the issue, explicit python removed.
Change-Id: If33baa7e7449f1a8a4a06cceefeb82dad2dc1577
Signed-off-by: Alon Bar-Lev <alon.barlev@gmail.com>