Address deprecation warning for start YARN 2.x (#292)

diff --git a/ansible/roles/hadoop/tasks/start-yarn.yml b/ansible/roles/hadoop/tasks/start-yarn.yml
index 10c0c45..af54c4b 100644
--- a/ansible/roles/hadoop/tasks/start-yarn.yml
+++ b/ansible/roles/hadoop/tasks/start-yarn.yml
@@ -18,7 +18,7 @@
 - name: "start hadoop yarn 2.x"
   command: "{{ hadoop_home }}/sbin/start-yarn.sh"
   register: start_yarn_result
-  changed_when: start_yarn_result.stdout | search("starting (:?resource|node)manager")
+  changed_when: start_yarn_result.stdout is search("starting (:?resource|node)manager")
   when: hadoop_major_version == '2'
 - name: "start hadoop yarn 3.x"
   command: "nohup {{ hadoop_home }}/sbin/start-yarn.sh"