Make IMAGE_TAG honor CIRCLE_TAG (#1632)

Signed-off-by: Goutham Veeramachaneni <[email protected]>

Author: gouthamve

integration-tests/common.sh

@@ -2,7 +2,7 @@
 
 TEST_DIR="$( cd "$(dirname "$0")" ; pwd -P )"
 
-IMAGE_TAG=$($TEST_DIR/../tools/image-tag)
+IMAGE_TAG=${CIRCLE_TAG:-$($TEST_DIR/../tools/image-tag)}
 
 COMMON_ARGS="-consul.hostname=consul:8500"
 STORAGE_ARGS="-config-yaml=/tests/schema1.yaml -dynamodb.url=dynamodb://u:[email protected].:8000"