ci(travis): enabling only 5 builds for Salt 2019.2 on py3

.travis.yml

@@ -20,20 +20,20 @@ env:
     - INSTANCE: default-centos-7-2019-2-py3
     - INSTANCE: default-fedora-29-2019-2-py3
     - INSTANCE: default-opensuse-leap-15-2019-2-py3
-    - INSTANCE: default-debian-9-2018-3-py2
-    - INSTANCE: default-ubuntu-1604-2018-3-py2
-    - INSTANCE: default-centos-7-2018-3-py2
-    - INSTANCE: default-fedora-29-2018-3-py2
-    # TODO: Use this when fixed instead of `opensuse-leap-42`
-    # Ref: https://github.com/netmanagers/salt-image-builder/issues/2
-    # - INSTANCE: default-opensuse-leap-15-2018-3-py2
-    - INSTANCE: default-opensuse-leap-42-2018-3-py2
-    - INSTANCE: default-debian-8-2017-7-py2
-    - INSTANCE: default-ubuntu-1604-2017-7-py2
-    # TODO: Enable after improving the formula to work with other than `systemd`
-    - INSTANCE: default-centos-6-2017-7-py2
-    - INSTANCE: default-fedora-28-2017-7-py2
-    - INSTANCE: default-opensuse-leap-42-2017-7-py2
+#    - INSTANCE: default-debian-9-2018-3-py2
+#    - INSTANCE: default-ubuntu-1604-2018-3-py2
+#    - INSTANCE: default-centos-7-2018-3-py2
+#    - INSTANCE: default-fedora-29-2018-3-py2
+#    # TODO: Use this when fixed instead of `opensuse-leap-42`
+#    # Ref: https://github.com/netmanagers/salt-image-builder/issues/2
+#    # - INSTANCE: default-opensuse-leap-15-2018-3-py2
+#    - INSTANCE: default-opensuse-leap-42-2018-3-py2
+#    - INSTANCE: default-debian-8-2017-7-py2
+#    - INSTANCE: default-ubuntu-1604-2017-7-py2
+#    # TODO: Enable after improving the formula to work with other than `systemd`
+#    - INSTANCE: default-centos-6-2017-7-py2
+#    - INSTANCE: default-fedora-28-2017-7-py2
+#    - INSTANCE: default-opensuse-leap-42-2017-7-py2
 
 script:
   - bundle exec kitchen verify ${INSTANCE}