Fix: making sure the file type is not overwritten by the last queried component
SNAPC: use dynamic buffers for rml.send and rml.recv

The snapc component was still using static buffers
for send_buffer_nb(). This patch changes opal_buffer_t buffer;
to opal_buffer_t *buffer;
SSTORE: use dynamic buffers for rml.send and rml.recv

The sstore component was still using static buffers
for send_buffer_nb(). This patch changes opal_buffer_t buffer;
to opal_buffer_t *buffer;