Update git submodules

* Update keystone from branch 'master'
  to c3bfa0924d82e52e9429575bcfeb8963f7df6dd8
  - Merge "Drop workaround for sphinx-feature-classification < 0.4.2"
  - Drop workaround for sphinx-feature-classification < 0.4.2

    Since 1fb0127663e65dad1c1f000e1dc94e2bc67fed19 was merged in 0.4.2,
    sphinx-feature-classification creates the destination directory if it
    does not exist.

    Change-Id: I17365023804e11581aa77ffe64af5dfca2a4a4c8
    Signed-off-by: Takashi Kajinami <kajinamit@oss.nttdata.com>

diff --git a/keystone b/keystone
index 44e058fe9ff67e1a70e27b511e8463aa7549f0be..c3bfa0924d82e52e9429575bcfeb8963f7df6dd8 160000 (submodule)
--- a/keystone
+++ b/keystone
@@ -1 +1 @@
-Subproject commit 44e058fe9ff67e1a70e27b511e8463aa7549f0be
+Subproject commit c3bfa0924d82e52e9429575bcfeb8963f7df6dd8