commit 2640010f690dab89fc444c803a10d783e9180357
Author: Stephen Finucane <sfinucan@redhat.com>
Date:   Mon Oct 5 18:14:27 2020 +0100

    Update git submodules
    
    * Update os-vif from branch 'master'
      - tox: Rename 'UPPER_CONSTRAINTS_FILE' -> 'TOX_CONSTRAINTS_FILE'
    
        This is the new name recommended by the base zuul jobs [1]:
    
          Path to a pip constraints file. Will be provided to tox via
          ``TOX_CONSTRAINTS_FILE`` (deprecated but currently still supported
          name is ``UPPER_CONSTRAINTS_FILE``) environment variable if it exists.
    
        While we're here, we remove a wholly unnecessary layer of environment
        variable-based indirection.
    
        [1] https://opendev.org/zuul/zuul-jobs/raw/branch/master/roles/tox/README.rst
    
        Change-Id: Ic82672f5376988ef6c40d2aaebf1a9e59d3538ad
        Signed-off-by: Stephen Finucane <sfinucan@redhat.com>

diff --git a/os-vif b/os-vif
index cc15462..4e6c160 160000
--- a/os-vif
+++ b/os-vif
@@ -1 +1 @@
-Subproject commit cc15462308e544981be58c4552a2593f5eb27b9c
+Subproject commit 4e6c16037c1139e189d2ec7b6a90b43c3b10b16b