Update git submodules

* Update keystone from branch 'master'
  to a903b505429410435aab4c96db6e89413929fcf3
  - Merge "Improve federated mapping documentation clarity"
  - Improve federated mapping documentation clarity

    Rewrote the federated mapping documentation because it had issues with
    missing information, incorrect information or examples that did not make
    sense. The layout of it resulted in some important pieces of information
    coming at the very end which could cause users to do the wrong thing if
    they did not read past sections that didn't pertain to them. Added more
    detailed examples of how each of the different mapping engine operations
    work. Documented up front how the different pieces of data are mapped
    and what must exist and what is created for you. Added a section about
    troubleshooting to help users determine what went wrong based on
    questions recently seen in the IRC channel. Removed confusing wording
    and used a consistent term throughout (e.g. assertion vs context
    variables). Added relative links to make the doc flow smoother.

    Change-Id: I7382998d02f11e19886c6b83e69c6a7d095a957a
    Assisted-by: Claude Sonnet 4.5
    Signed-off-by: Doug Goldstein <cardoe@cardoe.com>

diff --git a/keystone b/keystone
index e2d3c6fbf3fdb330fba46e4e2acb6b9e2cf91f92..a903b505429410435aab4c96db6e89413929fcf3 160000 (submodule)
--- a/keystone
+++ b/keystone
@@ -1 +1 @@
-Subproject commit e2d3c6fbf3fdb330fba46e4e2acb6b9e2cf91f92
+Subproject commit a903b505429410435aab4c96db6e89413929fcf3