emacsclient: tidy socket failure cleanup

emacsclient: tidy socket failure cleanup

* lib-src/emacsclient.c (set_tcp_socket, set_local_socket):
Close socket (instead of leaking it) when ‘connect’ fails.
(socket_status): Return errno if stat fails and -1 if we don’t own.
(set_local_socket): Simplify based on socket_status change.