Use tmp directory for the temporary file.

[kurtbgriffith]

Would it be possible to change line 9 of lib/util.js
from
var tempDeferredFilename = 'temp_deferred_' + Math.random() + '.tsv';
to
var tempDeferredFilename = '/tmp/temp_deferred_' + Math.random() + '.tsv';

This allows for better security while allowing other users such as a rundeck user to fire the parent process.

Thank you!