Update git submodules

* Update docs/submodules/functest from branch 'stable/fraser'
  - Merge "Get debug data before cleaning juju_epc" into stable/fraser
  - Get debug data before cleaning juju_epc

    It could help us to detect the issue when testing Apex (nosdn).
    It should be only printed on exceptions instead but this proposal is
    safer and straightforward.

    Change-Id: I2cccc737e3b3572af72c2653bf32bc02f9ab9077
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>
    (cherry picked from commit c789cca4a6e9afefba0c1622d49a181dd35437f7)

diff --git a/docs/submodules/functest b/docs/submodules/functest
index da20f16..15bed39 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit da20f16245506140b0912dd9580171f3c2c0dd96
+Subproject commit 15bed392750c02152ca10fed056a63b1eaee7cf2