Update git submodules

* Update docs/submodules/availability from branch 'master'
  - Merge "Add High Availability Analysis Document"
  - Add High Availability Analysis Document

    JIRA: HA-35

    Change-Id: I49d12916f41fa80313384205a334cb7fbfd46cee
    Signed-off-by: tjuyinkanglin <14_ykl@tongji.edu.cn>

diff --git a/docs/submodules/availability b/docs/submodules/availability
index 1c2ce63..30dcfd1 160000 (submodule)
--- a/docs/submodules/availability
+++ b/docs/submodules/availability
@@ -1 +1 @@
-Subproject commit 1c2ce630bf5eba741860232b89e67afc2f7cf71c
+Subproject commit 30dcfd148572763ff773e71dd67276e0c23925ea