Update git submodules

* Update docs/submodules/releng-xci from branch 'master'
  - Merge "xci: scripts: start-new-vm.sh: Improve do_copy()"
  - xci: scripts: start-new-vm.sh: Improve do_copy()

    The copy function of start-new-vm.sh script only excludes the
    image of the current OS which is some cases can contain other
    images. This change excludes any image.

    Change-Id: I50075cb56e7784d090582fe5d0c11c906773a174
    Signed-off-by: Victor Morales <victor.morales@intel.com>

diff --git a/docs/submodules/releng-xci b/docs/submodules/releng-xci
index a105e1a..6d6aaed 160000 (submodule)
--- a/docs/submodules/releng-xci
+++ b/docs/submodules/releng-xci
@@ -1 +1 @@
-Subproject commit a105e1a55d44c241d194c29ccc21aa8df0fe763b
+Subproject commit 6d6aaedfc699d5fd480b2c0b2af428dc0b5d6b46