Catch the exception when no XML files are found to lint

magento2-xml-lint/latest/xml-lint

@@ -17,7 +17,11 @@ def get_mappings(misc_file, base_dir):
     return mapping
 
 def get_xml_files(search_dir):
-    return check_output(['find', search_dir, '-name', '*.xml']).splitlines()
+    try:
+        return check_output(['find', search_dir, '-name', '*.xml']).splitlines()
+    except CalledProcessError:
+        print "WARNING: No XML files found"
+        return []
 
 def lint_only(file):
     try: