Merge #16491: qa: fix deprecated log.warn in feature_dbcrash test

62d3f50 qa: fix deprecated log.warn in feature_dbcrash test (Jon Atack)

Pull request description:

  This clears up the following deprecation message when running test/functional/feature_dbcrash.py:
  ```
  test/functional/feature_dbcrash.py:270:
  DeprecationWarning: The 'warn' method is deprecated, use 'warning' instead
    self.log.warn("Node %d never crashed during utxo flush!", i)
  ```

  Git grepping indicates that this was the last remaining use of `log.warn` in the functional tests.

ACKs for top commit:
  fanquake:
    ACK 62d3f50 - checked that there were no more occurrences.

Tree-SHA512: 2fe87400f82488e44391f4897876003a98736013e819a7dbc3b3e87a5ffbfba8d5ccab81cf2b7577f40135c95e4db96e93bb8cb24de396efb4ad814fbda09559

Author: fanquake

test/functional/feature_dbcrash.py

@@ -267,7 +267,7 @@ def run_test(self):
         # Warn if any of the nodes escaped restart.
         for i in range(3):
             if self.restart_counts[i] == 0:
-                self.log.warn("Node %d never crashed during utxo flush!", i)
+                self.log.warning("Node %d never crashed during utxo flush!", i)
 
 if __name__ == "__main__":
     ChainstateWriteCrashTest().main()