Fix syntax error in image URL

Closes-Bug: PROD-35400
Change-Id: I5f57f673c001a5d41e8e44fd7e8056424cc5ceb2
diff --git a/defaults/docker_images.yml b/defaults/docker_images.yml
index 53bf882..927687f 100644
--- a/defaults/docker_images.yml
+++ b/defaults/docker_images.yml
@@ -20,7 +20,7 @@
     docker_image_jenkins: "${_param:mcp_docker_registry}/mirantis/cicd/jenkins:2019.2.9"
     docker_image_jenkins_jnlp_slave: "${_param:mcp_docker_registry}/mirantis/cicd/jnlp-slave:2019.2.9"
     # TODO: fix tag
-    docker_image_jenkins_ssh_slave: "{_param:mcp_docker_registry}/mirantis/cicd/ssh-slave:2019.2.10"
+    docker_image_jenkins_ssh_slave: "${_param:mcp_docker_registry}/mirantis/cicd/ssh-slave:2019.2.10"
     # model-generator
     docker_image_operations_api: "${_param:mcp_docker_registry}/mirantis/model-generator/operations-api:2019.2.6"
     docker_image_operations_ui: "${_param:mcp_docker_registry}/mirantis/model-generator/operations-ui:2019.2.6"