Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "apiserver: mock socket.gethostbyname"
  - apiserver: mock socket.gethostbyname

    we don't want use external DNS requests during unittest

    Change-Id: I5ed67b700ef1dab4b650ae5071a3cf641a17ae4c
    Signed-off-by: Ross Brattain <ross.b.brattain@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index ae0cdbe..1e5e197 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit ae0cdbea1100a09d0c46191dd7e5d8d5eec8d484
+Subproject commit 1e5e1977fab21941e6bd2158e6cf10680ceaa2f6