spelling & edns_keepalive fix

Contributed by Josh Soref on github: https://github.com/CZ-NIC/knot-resolver/pull/75

bench/bench_lru.c

@@ -143,7 +143,7 @@ static struct key * read_lines(const char *fname, size_t *count, char **pfree)
 	return result;
 }
 
-// compatibility layer for the oler lru_* names; it's more compler with lru_create
+// compatibility layer for the older lru_* names
 #ifndef lru_create
 	#define lru_get_new lru_set
 	#define lru_get_try lru_get