manhattan node 0.8 doesn't have os.tmdir()

SD failed because [os.tmdir](http://nodejs.org/api/os.html#os_os_tmpdir) is missing, so use /tmp there.

![no method tmpdir](https://f.cloud.github.com/assets/46951/624728/034c08cc-cf8c-11e2-8e6b-99dad8bfef26.png)