Fix: relayd: possible NULL ptr deref, memory leak, accept fd leak

Fix: relayd: possible NULL ptr deref, memory leak, accept fd leak

- relay_cmd was not freed on error.
- newsock is a pointer. A pointer is always > 0. (unsigned comparison)
- if / else if  could lead to newsock to be dereferenced while NULL.
- missing lttcomm_destroy_sock on newsock on setsockopt error.
  Memory and FD leak.

Signed-off-by: Christian Babeux <christian.babeux@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>