Overwrite install.log instead of appending to it

[dlon]

Some sensitive information used to be logged here. This was fixed in #1521. But it could still end up in problem reports since updating the app only appended to the existing log. Fix by overwriting the file.

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This change is 

[mvd-ows]

Reviewed 2 of 2 files at r1.
Reviewable status: complete! all files reviewed, all discussions resolved

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windows/nsis-plugins/src/log/log.cpp, line 240 at r1 (raw file):

				const auto logfile = decltype(logpath)(logpath).append(L"install.log");

				g_logger = new Logger(std::make_unique<Utf8FileLogSink>(logfile, false));

I think it was I that added the optional argument? A better solution for modeling this is to use an enum, even when there are only two possible values.

Because then, the code at the call site is immensely more readable.

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windows/nsis-plugins/src/log/logger.cpp, line 29 at r1 (raw file):

		if (FALSE == seekStatus)
		{
			CloseHandle(m_logfile);

Good catch.