ci(travis): reduce number of travis jobs

.travis.yml

     # - env: INSTANCE=default-oraclelinux-7-tiamat-py3
     - env: INSTANCE=default-debian-10-master-py3
     - env: INSTANCE=default-ubuntu-2004-master-py3
-    - env: INSTANCE=default-ubuntu-1804-master-py3
+    # - env: INSTANCE=default-ubuntu-1804-master-py3
     - env: INSTANCE=default-centos-8-master-py3
     # - env: INSTANCE=default-fedora-32-master-py3
     # - env: INSTANCE=default-fedora-31-master-py3
     # - env: INSTANCE=default-opensuse-leap-152-master-py3
     # - env: INSTANCE=default-amazonlinux-2-master-py3
     # - env: INSTANCE=default-debian-10-3001-py3
-    - env: INSTANCE=default-debian-9-3001-py3
+    # - env: INSTANCE=default-debian-9-3001-py3
     # - env: INSTANCE=default-ubuntu-2004-3001-py3
     # - env: INSTANCE=default-ubuntu-1804-3001-py3
     # - env: INSTANCE=default-centos-8-3001-py3
     - env: INSTANCE=default-arch-base-latest-3000-3-py2
     # - env: INSTANCE=upstart-centos-6-2019-2-py2
     # - env: INSTANCE=upstart-amazonlinux-1-2019-2-py2
-    - env: INSTANCE=mysql-debian-10-master-py3
-    - env: INSTANCE=mysql-ubuntu-2004-master-py3
+    # - env: INSTANCE=mysql-debian-10-master-py3
+    - env: INSTANCE=mysql-debian-9-3001-py3
+    # - env: INSTANCE=mysql-ubuntu-2004-master-py3
+    # - env: INSTANCE=mysql-ubuntu-1804-master-py3
 
     ## Define the release stage that runs `semantic-release`
     - stage: 'release'

kitchen.yml

   - name: mysql
     includes:
       - debian-10-master-py3
+      - debian-9-3001-py3
       - ubuntu-2004-master-py3
+      - ubuntu-1804-master-py3
     provisioner:
       state_top:
         base:
           '*':
             - diaspora
+            - redis
             - mysql
       pillars:
         top.sls:
         tests.sls: test/salt/pillar/tests.sls
         mysql.sls: test/salt/pillar/mysql.sls
       dependencies:
+        - name: redis
+          path: test/salt/states
         - name: mysql
           path: test/salt/states
     verifier: