Temporarily disable swift-dsvm-functional for Icehouse

This is needed to unblock other fixes in gate.

The gate fails as follows: swift-dsvm-functional attempts to execute
tox -e func environment [1] but it's not available (backport of the env
is at [2]).

[1]: http://logs.openstack.org/54/157654/2/check/check-swift-dsvm-functional/eb343e3/console.html
[2]: https://review.openstack.org/#/c/157670/

Related-Bug: #1423753
Change-Id: Id46475f809c1a06789326e25a3e1825e3e572f4e

zuul/layout.yaml

@@ -890,6 +890,11 @@ jobs:
   # TODO(cschwede): Enable voting when there is enough data
   - name: check-swiftclient-dsvm-functional
     voting: false
+  # TODO(ihrachys): temporarily disable to unblock gate
+  - name: check-swift-dsvm-functional
+    branch: ^(?!stable/icehouse).*$
+  - name: gate-swift-dsvm-functional
+    branch: ^(?!stable/icehouse).*$
   - name: gate-kolla-bashate
     voting: false
   - name: ^(gate-)?devstack-publish-docs