Right after starting the communication with orterun the buffer
containing the message is deleted. This patch removes the deletion
of the buffer which is now done by orte_rml_send_callback(). This is
now also the callback function used by orte_rml.send_buffer_nb().
The previous callback hnp_receiver() was introduced by an
earlier patch which only was trying to get the code to compile again.
This commit was SVN r30405.
919260a0d2