Release os-vif for stable/xena

This release picks up new commits to os-vif since
the last release from stable/xena.

This is being proposed as a convenience to help make sure stable
changes are being released. If the team is good with this going out,
please respond with a +1 to let the release team know it is OK to
proceed.

If it is not wanted at this time, or if there are more changes that
would be good to get merged before doing a stable release, please
leave a -1 with a comment with what the team would prefer. We can
then either abandon this patch, or wait for an update with a new
commit hash to use instead.

$ git log --oneline --no-merges 2.6.0..8d14a1c
8d14a1c Move mtu update request into ovsdb transaction
e6e791b only register tables used by os-vif
26f073f Use TCP keepalives for ovsdb connections
1e219a6 Update TOX_CONSTRAINTS_FILE for stable/xena
6d58597 Update .gitreview for stable/xena

Signed-off-by: Hervé Beraud <hberaud@redhat.com>
Change-Id: Ife8610f2e932b5b9ecf2a78dc51884a1a91379fe

deliverables/xena/os-vif.yaml

@@ -16,6 +16,10 @@ releases:
     projects:
       - repo: openstack/os-vif
         hash: b837c1a74f37191692a820711e431a75516a4abf
+  - version: 2.6.1
+    projects:
+      - repo: openstack/os-vif
+        hash: 8d14a1c6a9eeaef0fdae9ea1210d3310a3498d78
 branches:
   - name: stable/xena
     location: 2.6.0