[0.4.9] [SETUPAPI] Apply yet uncommitted fix for CORE-12616 PR-408

[0.4.9] [SETUPAPI] Apply yet uncommitted fix for CORE-12616 PR-408

This commit was *not* committed to master yet.
I'll leave the ticket unresolved until it'll be.

This fixes a regression introduced in SVN r73442:
Our setup created undesired temporary files and left them
in the temp folder. Also we saw a slight one-time-increase
in memory consumption.

This patch was the work of Carlo Bramini
He proposed the fix on 2016-12-30 already.

There are ongoing discussions about an alternative approach
to the initial problem that SVN r73442 tried to address.
Serge Gautherie can and shall be evaluate that alternative
later during 0.4.10dev.

For now many thanks to Carlo Bramini for this fix.

(cherry picked from commit dba2f743c586395c4cccb68e742a1273d0d310a9)