FileReadingMessageSource supports disposition of the payload
after the message is sent (or via transaction synchronization).
The (S)FTP adapters delegate to an FRMS; add support for the
file disposition expression, result channel, and send timeout
to the (S)FTP adapters.
Also tested with ftp sample - INTSAMPLES-83 - patch will be
committed once this is in a milestone.
e6e43100b5