Update git submodules

* Update docs/submodules/armband from branch 'master'
  - u/fuel: Bump & rebase for openstack fix

    Change-Id: I5d48b6cd8ad2b1d602ed86d5d1f69a0a806bc170
    Signed-off-by: Guillermo Herrero <guillermo.herrero@enea.com>

diff --git a/docs/submodules/armband b/docs/submodules/armband
index 901e1e7..6657baa 160000 (submodule)
--- a/docs/submodules/armband
+++ b/docs/submodules/armband
@@ -1 +1 @@
-Subproject commit 901e1e70ec43c716430e58ee7148bc2cb9b64f6f
+Subproject commit 6657baa68d238e1cba9e1d69118616e438b07f37