dummymbuf: Log the entire rule set if no delimiters are present

An empty string was printed instead.

Reviewed by:	kp
Approved by:	kp (mentor)
Differential Revision:	https://reviews.freebsd.org/D46964

sys/net/dummymbuf.c

@@ -223,6 +223,7 @@ read_rule(const char **cur, struct rule *rule, bool *eof)
 	while (**cur == ' ')
 		(*cur)++;
 	rule->syntax_begin = *cur;
+	rule->syntax_len = strlen(rule->syntax_begin);
 
 	/* syntax_len */
 	char *delim = strchr(*cur, ';');