Update git submodules

* Update upstream/fuel from branch 'stable/colorado'
  - [virtual envs] Switch to raw images

    * use raw devices instead of qcow2
    * disable i/o caching, it reduces data copies and bus traffic
    * set native aio instead of thread based

    JIRA: FUEL-201
    Change-Id: I8ac728cbb5be5948080fab8ae4d3d311e0a5c09c
    Signed-off-by: Michael Polenchuk <mpolenchuk@mirantis.com>
    (cherry picked from commit ed79331c115eac4aad0eccd4b191c9e1e836c73d)

diff --git a/upstream/fuel b/upstream/fuel
index c113370..771761f 160000 (submodule)
--- a/upstream/fuel
+++ b/upstream/fuel
@@ -1 +1 @@
-Subproject commit c11337074cfa0d520fb3fa876965e420fd7145e3
+Subproject commit 771761f708e6cb61fba99abf67a07111e1c75470