Add ability to choose OS version in tests

This commit adds possibility to run kitchen
tests on different Openstack versions. By default
ocata release will be tested.

Also, run_tests.sh fixed to not to check pillars
which don't contain cinder dict.

Change-Id: Ie1d6b9a3f8e8e0d26852a5d010f88abdb1d75f71
Related-Prod: OSCORE-451
diff --git a/.travis.yml b/.travis.yml
index 77f72c9..9570c9b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -17,26 +17,26 @@
   - bundle install
 
 env:
-    - PLATFORM=trevorj/salty-whales:trusty SUITE=ceph_single
-    - PLATFORM=trevorj/salty-whales:xenial SUITE=ceph_single
-    - PLATFORM=trevorj/salty-whales:trusty SUITE=control_cluster
-    - PLATFORM=trevorj/salty-whales:xenial SUITE=control_cluster
-    - PLATFORM=trevorj/salty-whales:trusty SUITE=control_single
-    - PLATFORM=trevorj/salty-whales:xenial SUITE=control_single
-    - PLATFORM=trevorj/salty-whales:trusty SUITE=gpfs_single
-    - PLATFORM=trevorj/salty-whales:xenial SUITE=gpfs_single
-    - PLATFORM=trevorj/salty-whales:trusty SUITE=hp3par_single
-    - PLATFORM=trevorj/salty-whales:xenial SUITE=hp3par_single
-    - PLATFORM=trevorj/salty-whales:trusty SUITE=lefthand_single
-    - PLATFORM=trevorj/salty-whales:xenial SUITE=lefthand_single
-    - PLATFORM=trevorj/salty-whales:trusty SUITE=solidfire_single
-    - PLATFORM=trevorj/salty-whales:xenial SUITE=solidfire_single
-    - PLATFORM=trevorj/salty-whales:trusty SUITE=storwize_single
-    - PLATFORM=trevorj/salty-whales:xenial SUITE=storwize_single
-    - PLATFORM=trevorj/salty-whales:trusty SUITE=volume_single
-    - PLATFORM=trevorj/salty-whales:xenial SUITE=volume_single
-    - PLATFORM=trevorj/salty-whales:trusty SUITE=vsp_single
-    - PLATFORM=trevorj/salty-whales:xenial SUITE=vsp_single
+    - PLATFORM=trevorj/salty-whales:trusty OS_VERSION=mitaka SUITE=ceph_single
+    - PLATFORM=trevorj/salty-whales:xenial OS_VERSION=ocata SUITE=ceph_single
+    - PLATFORM=trevorj/salty-whales:trusty OS_VERSION=mitaka SUITE=control_cluster
+    - PLATFORM=trevorj/salty-whales:xenial OS_VERSION=ocata SUITE=control_cluster
+    - PLATFORM=trevorj/salty-whales:trusty OS_VERSION=mitaka SUITE=control_single
+    - PLATFORM=trevorj/salty-whales:xenial OS_VERSION=ocata SUITE=control_single
+    - PLATFORM=trevorj/salty-whales:trusty OS_VERSION=mitaka SUITE=gpfs_single
+    - PLATFORM=trevorj/salty-whales:xenial OS_VERSION=ocata SUITE=gpfs_single
+    - PLATFORM=trevorj/salty-whales:trusty OS_VERSION=mitaka SUITE=hp3par_single
+    - PLATFORM=trevorj/salty-whales:xenial OS_VERSION=ocata SUITE=hp3par_single
+    - PLATFORM=trevorj/salty-whales:trusty OS_VERSION=mitaka SUITE=lefthand_single
+    - PLATFORM=trevorj/salty-whales:xenial OS_VERSION=ocata SUITE=lefthand_single
+    - PLATFORM=trevorj/salty-whales:trusty OS_VERSION=mitaka SUITE=solidfire_single
+    - PLATFORM=trevorj/salty-whales:xenial OS_VERSION=ocata SUITE=solidfire_single
+    - PLATFORM=trevorj/salty-whales:trusty OS_VERSION=mitaka SUITE=storwize_single
+    - PLATFORM=trevorj/salty-whales:xenial OS_VERSION=ocata SUITE=storwize_single
+    - PLATFORM=trevorj/salty-whales:trusty OS_VERSION=mitaka SUITE=volume_single
+    - PLATFORM=trevorj/salty-whales:xenial OS_VERSION=ocata SUITE=volume_single
+    - PLATFORM=trevorj/salty-whales:trusty OS_VERSION=mitaka SUITE=vsp_single
+    - PLATFORM=trevorj/salty-whales:xenial OS_VERSION=ocata SUITE=vsp_single
 
 before_script:
   - set -o pipefail