Since 5.10 (commit 0dee566e98 in qtbase) Qt complains if we make a
system call with an empty filename (with a "Empty filename passed to
function" runtime warning).
I even hit an assert with my self-compiled build:
ASSERT: "unnamedFile == d_func()->fileEntry.isEmpty()"
(in qtemporaryfile.cpp, line 514).
The problem is that after socketfile.remove() we get an empty
fileName() which will be a problem when the QTemporaryFile gets
destroyed at the end of the if() block.
To avoid this issue we disable the autoremove mode.