Ensure volume is deleted after build error

When creating a test server and the volume fails to build
a VolumeResourceBuildErrorException is raised causing a resource
leak on the testing system[1]

This change aims to remove the volume before raising the exception
to the calling test so that the system is properly cleaned up of
testing resources before exiting.

[1] http://paste.openstack.org/show/743062/

Change-Id: Ib064e4f2cb113f98da73db519d855fa892515f66
diff --git a/tempest/common/compute.py b/tempest/common/compute.py
index 375113d..1489e60 100644
--- a/tempest/common/compute.py
+++ b/tempest/common/compute.py
@@ -168,10 +168,19 @@
                   'imageRef': image_id,
                   'size': CONF.volume.volume_size}
         volume = volumes_client.create_volume(**params)
-        waiters.wait_for_volume_resource_status(volumes_client,
-                                                volume['volume']['id'],
-                                                'available')
-
+        try:
+            waiters.wait_for_volume_resource_status(volumes_client,
+                                                    volume['volume']['id'],
+                                                    'available')
+        except Exception:
+            with excutils.save_and_reraise_exception():
+                try:
+                    volumes_client.delete_volume(volume['volume']['id'])
+                    volumes_client.wait_for_resource_deletion(
+                        volume['volume']['id'])
+                except Exception as exc:
+                    LOG.exception("Deleting volume %s failed, exception %s",
+                                  volume['volume']['id'], exc)
         bd_map_v2 = [{
             'uuid': volume['volume']['id'],
             'source_type': 'volume',