tor/changes/ticket33619

  o Major bugfixes (circuit padding, memory leaks):
    - Avoid a remotely triggered memory leak in the case that a circuit
      padding machine is somehow negotiated twice on the same circuit. Fixes
      bug 33619; bugfix on 0.4.0.1-alpha.  Found by Tobias Pulls.  This is
      also tracked as TROVE-2020-004.