Update git submodules

* Update manila-tempest-plugin from branch 'master'
  to 2931c8807388da7b1e5909ac2d6ffb2d37e63ddd
  - Merge "Remove Wallaby jobs"
  - Remove Wallaby jobs

    stable/wallaby was retired long ago.

    Change-Id: Ib0324392651365b767e407701dc1dbd09cbf67ea
    Signed-off-by: Takashi Kajinami <kajinamit@oss.nttdata.com>

diff --git a/manila-tempest-plugin b/manila-tempest-plugin
index 283b664c8be0655bcf370bce10c851cf8dacd2c6..2931c8807388da7b1e5909ac2d6ffb2d37e63ddd 160000 (submodule)
--- a/manila-tempest-plugin
+++ b/manila-tempest-plugin
@@ -1 +1 @@
-Subproject commit 283b664c8be0655bcf370bce10c851cf8dacd2c6
+Subproject commit 2931c8807388da7b1e5909ac2d6ffb2d37e63ddd