sctp cfg typo fix

- typo fixed in cfg.lex (the options for setting the send or receive buffer
sizes did not work)

cfg.lex

@@ -325,8 +325,8 @@ TLS_HANDSHAKE_TIMEOUT	"tls_handshake_timeout"
 TLS_SEND_TIMEOUT	"tls_send_timeout"
 DISABLE_SCTP	"disable_sctp"
 SCTP_CHILDREN	"sctp_children"
-SCTP_SOCKET_RCVBUF	"sctp_socket_rcvbuf|sctp_socket_receive_buffer"
-SCTP_SOCKET_SNDBUF	"sctp_socket_sndbuf|sctp_socket_send_buffer"
+SCTP_SOCKET_RCVBUF	"sctp_socket_rcvbuf"|"sctp_socket_receive_buffer"
+SCTP_SOCKET_SNDBUF	"sctp_socket_sndbuf"|"sctp_socket_send_buffer"
 SCTP_AUTOCLOSE	"sctp_autoclose"
 SCTP_SEND_TTL	"sctp_send_ttl"
 ADVERTISED_ADDRESS	"advertised_address"