Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Replace neutron floating ip deletion with shade."
  - Replace neutron floating ip deletion with shade.

    Function delete_floating_ip now uses shade client.

    JIRA: YARDSTICK-890

    Change-Id: I960630926b664266afbe7be00bb1352243b41be0
    Signed-off-by: Shobhi Jain <shobhi.jain@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 1f4a426..06f089d 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 1f4a42675dd70e6051b06c1c11c0d5db03caada8
+Subproject commit 06f089db5fa9de1fd05e37122afad6555d50265d