zuul-var-to-json: parameterization of the target path

Change-Id: I7f67bfccffeed32ddfa3c7e033cb401c0806598c
diff --git a/roles/run-test-command/meta/main.yaml b/roles/run-test-command/meta/main.yaml
index 7767619..a239d8f 100644
--- a/roles/run-test-command/meta/main.yaml
+++ b/roles/run-test-command/meta/main.yaml
@@ -1,3 +1,4 @@
 ---
 dependencies:
   - role: zuul-var-to-json
+    zuul_env_json_file: '{{ ansible_user_dir }}/zuul-env.json'