A custom '=destroy' hook which takes a 'var T' parameter is deprecated

[MauroG]

@ggibson

sorry if I mention you again but I don't understand how I should replace this 
code:
    
    
    proc freeConnection*(con: ODBCConnection) =
      con.disconnect
      if con.envHandle != nil:
        freeEnvHandle(con.envHandle, con.reporting)
    
    
    
    Run

to have destroy hooks.