Fix memory leak in case of cert key mismatch, thanks to @disaykin

src/opts.c

@@ -109,6 +109,7 @@ opts_load_cert_chain_key(const char *filename)
 		log_err_level_printf(LOG_CRIT, "Cert does not match key in PEM file "
 		                "'%s':\n", filename);
 		ERR_print_errors_fp(stderr);
+		cert_free(cert);
 		return NULL;
 	}