Fixes Heat tempest issue due to hardcoded qcow2 extension

The orchestration image_ref is set incorrectly if the extension is not
qcow2, as a result tempest cannot find the Glance image and the
associated tests fail.

This patch fixes the issue by handling any extension.

Change-Id: I32ffe021714590a1b1bab232b1d4f5da238bd4d8
Closes-Bug: #1402774
diff --git a/lib/tempest b/lib/tempest
index 6fc157f..7cac6dd 100644
--- a/lib/tempest
+++ b/lib/tempest
@@ -372,7 +372,7 @@
     # Orchestration Tests
     if is_service_enabled heat; then
         if [[ ! -z "$HEAT_CFN_IMAGE_URL" ]]; then
-            iniset $TEMPEST_CONFIG orchestration image_ref $(basename "$HEAT_CFN_IMAGE_URL" ".qcow2")
+            iniset $TEMPEST_CONFIG orchestration image_ref $(basename "${HEAT_CFN_IMAGE_URL%.*}")
         fi
         # build a specialized heat flavor
         available_flavors=$(nova flavor-list)