Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Improve SampleVNF hugepages setup"
  - Improve SampleVNF hugepages setup

    The goal of this function is to:
    - Read the default hugepage size.
    - Set 16GB of hugepages.
    - Check if the status of the last action.

    According to [1], the default hugepage size could be read in
    "/proc/meminfo", always in kB. Then "/proc/sys/vm/nr_hugepages"
    could be used to set the number of default hugepages.

    [1] https://www.kernel.org/doc/Documentation/vm/hugetlbpage.txt

    JIRA: YARDSTICK-997

    Change-Id: I762d1b16294ba1c1c2feee56610819ac358c7410
    Signed-off-by: Rodolfo Alonso Hernandez <rodolfo.alonso.hernandez@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index ebbb901..3387e56 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit ebbb901b84a4f53480d362eba0a51886f26e87f0
+Subproject commit 3387e5618de37c37714c86cec9058d737cb01a5c