Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Merge "Modify TestCase.__str__() to use PrettyTable"
  - Modify TestCase.__str__() to use PrettyTable

    It adds PrettyTable as requirement even if it's already defined in
    OpenStack client dependencies.

    If the TestCase object is considered as invalid, it simply returns the
    default str.

    Change-Id: Iee788aef2a13694d9482560977cbbf21c7f2c967
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/functest b/docs/submodules/functest
index 696fb16..ccb98c2 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit 696fb168cd72978c18a9c7f4d9d2ba60b80611ab
+Subproject commit ccb98c22390fd97a3bb55aa225c7241cc4daa85d