SPARK-4507: try to resolve issue when no JIRAs in title

Author: hase1031

dev/merge_spark_pr.py

@@ -278,6 +278,8 @@ def get_version_json(version_str):
 def resolve_jira_issues(title, merge_branches, comment):
     jira_ids = re.findall("SPARK-[0-9]{4,5}", title)
 
+    if len(jira_ids) == 0:
+        resolve_jira_issue(merge_branches, comment)
     for jira_id in jira_ids:
         resolve_jira_issue(merge_branches, comment, jira_id)