Update git submodules

* Update nova from branch 'master'
  to 11dff40b4fba04e1423fb1ffe3866f59f5325a6e
  - Merge "Make image upload tpool usage conditional"
  - Make image upload tpool usage conditional

    When running in eventlet mode we keep the original eventlet.tpool usage
    but when running in threading mode we call the functions directly on the
    thread of the caller.

    The original tpool_execute() call made the upload call running in a
    native tread as it has parts that are blocking and therefore running
    them in the current greenthread would make the other greenthreads
    starved.

    After this patch we preserve the same effect but with different syntax.
    We use tpool_wrap to wrap the function into a tpool.Proxy object and
    then call the proxy object. That proxy ensures that any call on the
    proxy object is run in a native thread.

    This change is useful for us in native threaded mode. There the
    tpool_wrap returns the function unchanged. So upload is executed in the
    caller's native thread. This is OK as in native threaded mode any
    concurrent tasks are also in native threads and native threads are
    preempted when needed. So other tasks will not be starved.

    Change-Id: Iddb8b317b7a883c6fd144a93aca862a792fcd1af
    Signed-off-by: Balazs Gibizer <gibi@redhat.com>

diff --git a/nova b/nova
index 5b540e579e41a4f477d286fb443a9979b52f559c..11dff40b4fba04e1423fb1ffe3866f59f5325a6e 160000 (submodule)
--- a/nova
+++ b/nova
@@ -1 +1 @@
-Subproject commit 5b540e579e41a4f477d286fb443a9979b52f559c
+Subproject commit 11dff40b4fba04e1423fb1ffe3866f59f5325a6e