BUG/MINOR: ssl: fix memory leak on realloc failure in acme.ips

Fix a realloc() bug in ckchs_dup() when copying the acme.ips array,
where overwriting the original pointer with NULL on allocation failure
loses reference to the original memory block.

Use my_realloc2() which safely handles the failure.

No backport needed.

src/ssl_ckch.c

@@ -1119,7 +1119,7 @@ struct ckch_store *ckchs_dup(const struct ckch_store *src)
 		/* copy the array of IP strings */
 
 		while (src->conf.acme.ips[n]) {
-			r = realloc(r, sizeof(char *) * (n + 2));
+			r = my_realloc2(r, sizeof(char *) * (n + 2));
 			if (!r)
 				goto error;