Update git submodules

* Update docs/submodules/stor4nfv from branch 'master'
  - ceph: shared persistent read-only rbd cache

    This patch introduces introduces RBD shared persistent RO cache which
    can provide client-side sharing cache for rbd clone/snapshot case.

    Change-Id: Icad8063f4f10b1ab4ce31920e90d5affa7d0abdc
    Signed-off-by: Qiaowei Ren <qiaowei.ren@intel.com>
    Signed-off-by: Dehao Shang <dehao.shang@intel.com>
    Signed-off-by: Tushar Gohad <tushar.gohad@intel.com>
    Signed-off-by: Jason Dillaman <dillaman@redhat.com>
    Signed-off-by: Yuan Zhou <yuan.zhou@intel.com>

diff --git a/docs/submodules/stor4nfv b/docs/submodules/stor4nfv
index 828acdd..d65e22d 160000 (submodule)
--- a/docs/submodules/stor4nfv
+++ b/docs/submodules/stor4nfv
@@ -1 +1 @@
-Subproject commit 828acdd1d5c5c2aeef287aa69e473bf44fcbce70
+Subproject commit d65e22d27ab305d38059046dae60d7a66ff4a4e0