Add MySQLMetaImpl::HasNonIndexFiles

Former-commit-id: 9db26bc1ecb99c3522f6a4743da75fc3088fbb5e

cpp/CHANGELOG.md

@@ -19,6 +19,7 @@ Please mark all change in change log and use the ticket from JIRA.
 - MS-230 - Change parameter name: Maximum_memory to insert_buffer_size
 - MS-234 - Some case cause background merge thread stop
 - MS-235 - Some test cases random fail
+- MS-236 - Add MySQLMetaImpl::HasNonIndexFiles
 
 ## Improvement
 - MS-156 - Add unittest for merge result functions