ui-blob: fix resource leak: free before return

Coverity-id: 13944
Signed-off-by: Christian Hesse <mail@eworm.de>

ui-blob.c

@@ -171,4 +171,5 @@ void cgit_print_blob(const char *hex, char *path, const char *head, int file_onl
 	ctx.page.filename = path;
 	cgit_print_http_headers();
 	html_raw(buf, size);
+	free(buf);
 }