Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Print the stack traceback when cleaning juju_epc

    Change-Id: If32557a4384cafd67b7c294f8c0592ee2769b1a5
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/functest b/docs/submodules/functest
index c97b870..b2b1be2 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit c97b870f9875a7b09bf0fdb059b24f963da2e4c2
+Subproject commit b2b1be21af5de2dd88092be268ae5f817608ecd1