Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Merge "Remove explicit Rally task validation"
  - Remove explicit Rally task validation

    Utilize the output of Rally task execution since it internally
    validates the task.

    Use Popen.communicate to get the output from the running Rally task.

    Change-Id: I9b1299bc26129ff4f89adccec611c78195a3ab02
    Signed-off-by: Juha Kosonen <juha.kosonen@nokia.com>

diff --git a/docs/submodules/functest b/docs/submodules/functest
index 5ece152..e8cd8e7 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit 5ece1528f52fc9b759e103e40375f40db1abc4b5
+Subproject commit e8cd8e7bd86a1b2d5fa952711ff854ed7b4982c2