ssa.c: In ssa_rsend_continue, add rsocket info to error log message

Signed-off-by: Hal Rosenstock <hal@mellanox.com>
ssa.c: Handle error events for rsockets which are listening

In ssa_downstream_handler, handle POLLERR, POLLHUP, and POLLNVAL events

Signed-off-by: Hal Rosenstock <hal@mellanox.com>
ssa.c: In ssa_close_ssa_conn, add log message before closing rsocket

Signed-off-by: Hal Rosenstock <hal@mellanox.com>
ssa.c: Add rsocket info to many log messages

Signed-off-by: Hal Rosenstock <hal@mellanox.com>