landlock: fix inconsistent error msg format in create

Make the error message format in `ll_create_full_ruleset` match the
other ones in landlock.c.

This amends commit 01a9ddb ("landlock: improve logs for debugging",
2023-11-08).

Misc: This was noticed on #6195.

Relates to #6078.

src/firejail/landlock.c

@@ -106,7 +106,7 @@ static int ll_create_full_ruleset(void) {
 
 	int ruleset_fd = landlock_create_ruleset(&attr, sizeof(attr), 0);
 	if (ruleset_fd < 0) {
-		fprintf(stderr, "%s: Error: failed to create Landlock ruleset "
+		fprintf(stderr, "Error: %s: failed to create Landlock ruleset "
 		                "(abi=%d fs=%llx): %s\n",
 		        __func__, ll_abi, attr.handled_access_fs,
 		        strerror(errno));