come back after a downtime. The STOP_OPERATION packet was never deleted from the
input buffer when OperationFailure was raised. The input & ouput buffers no more
use string list but one string only, performances should not be affected.


git-svn-id: https://svn.erp5.org/repos/neo/branches/prototype3@460 71dcc9de-d417-0410-9af5-da40c76e7ee4