Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "DRAFT: model: remove vld_id not needed"
  - DRAFT: model: remove vld_id not needed

    it seems vld_id is not needed now that
    we add it in _resolve_topology.

    Remove it from the model and Heat context first
    and see what happens

    Needs testing

    Change-Id: I30d13c80bd90246ee3be67a2bd3439db45e20bcd
    Signed-off-by: Ross Brattain <ross.b.brattain@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 96b4d98..2c76fe2 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 96b4d985bb8d83751e65a3ad5fa710e9eeddcb9b
+Subproject commit 2c76fe2cdc8c3f5ff5101e80f0621da33fbfbe4f