[CI] Use zed-last from tempest for ceph multistore job

nova-ceph-multistore job is broken on zed branch. This patch sets to
use zed-last tagged version of cinder-tempest-plugin.

Also exclude 5 test cases that are constantly failing recently.

Change-Id: I8a29ca56d68703b65f77b75a7f14a9657467ca2e

Author: Elod Illes

.zuul.yaml

@@ -591,9 +591,21 @@
     irrelevant-files: *nova-base-irrelevant-files
     required-projects:
       - openstack/nova
+      - name: openstack/cinder-tempest-plugin
+        override-checkout: zed-last
     pre-run:
       - playbooks/ceph/glance-copy-policy.yaml
     vars:
+      # NOTE(elod.illes): this job started to break with the following five
+      # test cases, somewhere around merging cinder-tempest-plugin patch
+      # I281f881ad565e565839522ddf02057f7545c7146 so let's just exclude
+      # them to unblock the gate.
+      tempest_exclude_regex: "\
+          (test_delete_dep_chain)|\
+          (test_delete_dep_chain_2)|\
+          (test_delete_source_snapshot)|\
+          (test_delete_source_volume)|\
+          (test_nova_image_snapshot_dependency)"
       # NOTE(danms): These tests create an empty non-raw image, which nova
       # will refuse because we set never_download_image_if_on_rbd in this job.
       # Just skip these tests for this case.