Delete some comment or messages of keystone_data.sh(removed)
As files/keystone_data.sh has been removed in the commit
https://review.openstack.org/#/c/79366/, we should remove some
related documations and comments.
Change-Id: I7802d0052fa28d8debb7f361d36a4f108869554c
diff --git a/HACKING.rst b/HACKING.rst
index 6bd24b0..d66687e 100644
--- a/HACKING.rst
+++ b/HACKING.rst
@@ -250,8 +250,7 @@
database access from the exercise itself.
* If specific configuration needs to be present for the exercise to complete,
- it should be staged in ``stack.sh``, or called from ``stack.sh`` (see
- ``files/keystone_data.sh`` for an example of this).
+ it should be staged in ``stack.sh``, or called from ``stack.sh``.
* The ``OS_*`` environment variables should be the only ones used for all
authentication to OpenStack clients as documented in the CLIAuth_ wiki page.