Update git submodules

* Update docs/submodules/barometer from branch 'master'
  - Updates OpenStack plugins information

    * Adds Aodh plugin description
    * Adds Gnocchi plugin description
    * Removes Ceilometer plugin
      * Makes reference to Ceilometer in a demo generic
    * Adds link to collectd-ceiloemter plugin GSG for
      configuration instructions

    Change-Id: I87a68f943c6e30a9fbabd6e3742978ca064e0c7a
    Signed-off-by: Emma Foley <emma.l.foley@intel.com>

diff --git a/docs/submodules/barometer b/docs/submodules/barometer
index f56d04d..6c0c441 160000 (submodule)
--- a/docs/submodules/barometer
+++ b/docs/submodules/barometer
@@ -1 +1 @@
-Subproject commit f56d04d684f5ccae7815960e9282c394545e3856
+Subproject commit 6c0c441e0678ade77c5242f83520f2dc3b5ddef1