The LSIF parser/transformer in Workhorse stores data in anonymous
tempfiles. Prior to this commit, Rails could dictate in what directory
those tempfiles were created. This is pointless because the reason we
use configurable tempdirs is to enable atomic renames, and you cannot
rename an anonymous file.

If the administrator wants to control where tempfiles get stored they
can still do so by setting the TMPDIR environment variable.

Changelog: other