adjust swift testing definitions to things that actually test swift

Based on analysis and mailing list conversations:

http://lists.openstack.org/pipermail/openstack-dev/2014-November/051501.html

We were running a lot of jobs on swift that weren't actually testing
swift in any meaningfully unique way. Reduce the set of jobs run on
swift to things that we believe provide meaningful feedback.

Change-Id: I74b678f3fa3ccbffae29d9e63f5d22f36f413c35

zuul/layout.yaml

@@ -1440,20 +1440,20 @@ projects:
       - name: python-jobs
       - name: openstack-server-publish-jobs
       - name: check-requirements
-      - name: integrated-gate
-      - name: large-ops
       - name: translation-jobs
       - name: experimental-tripleo-jobs
     check:
       - gate-swift-python26
       - gate-swift-tox-func
+      - check-tempest-dsvm-full
+      - check-grenade-dsvm
       - check-swift-dsvm-functional
-      - check-devstack-dsvm-cells
     gate:
       - gate-swift-python26
       - gate-swift-tox-func
+      - gate-tempest-dsvm-full
+      - gate-grenade-dsvm
       - gate-swift-dsvm-functional
-      - gate-devstack-dsvm-cells
     post:
       - swift-coverage
     experimental: