Update git submodules

* Update docs/submodules/joid from branch 'stable/fraser'
  - making default series to xenial.

    Change-Id: I26dfb8941e7b00717121dac3f1b3ecb26d8210bb
    Signed-off-by: Narinder Gupta <narinder.gupta@canonical.com>
    (cherry picked from commit 5235de0b3205b6d7e9c63cc85600927226a755d6)

diff --git a/docs/submodules/joid b/docs/submodules/joid
index 91a9e40..a9ea89a 160000 (submodule)
--- a/docs/submodules/joid
+++ b/docs/submodules/joid
@@ -1 +1 @@
-Subproject commit 91a9e4088e5d7bc660150afb0d1fbe26fb37d6ce
+Subproject commit a9ea89a4bc4258e1aceb0f7aef4b2af5506b212b