Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Run script only if volume device is found

    Add back volume device name search on instance.
    If vol is not attached script should not run.
    In the current state, if volume is not found, write_data returns
    positive result and read_data cannot find any new file

    Change-Id: Ifaa8af1e6d5c66f5ac776c83bebde526e77a9fd8
    Signed-off-by: Delia Popescu <delia.popescu@enea.com>

diff --git a/docs/submodules/functest b/docs/submodules/functest
index 4f89564..77b42be 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit 4f89564b20e9c3462614706a616d469540631786
+Subproject commit 77b42be3030c6e57f1a47cfd7a42a098a52902b8