ssa.c: In ssa_upstream_handle_op, free header memory for SSA_MSG_DB_UPDATE

hdr is same as svc->conn_dataup.rbuf
Also, removed unneeded clear of svc->conn_dataup.rhdr

Signed-off-by: Hal Rosenstock <hal@mellanox.com>
ssa.c: In ssa_upstream_handle_op, fix memory leak in error cases

when SSA_MSG_DB_PUBLISH_EPOCH_BUF or unknown op, free header
and clear svc->conn_dataup.rbuf

Signed-off-by: Hal Rosenstock <hal@mellanox.com>
ssa.c: In ssa_upstream_rrecv, fix case when header is not valid

In this case, deallocate the header and clear svc->conn_dataup.rbuf

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