bitcoin/bitcoin — pull request #852 by dooglus (2012-02-16 20:12:44+00:00)
Title: Fix #846. Allow negative options such as "nolisten=1" in bitcoin.conf as well as on the command line.

In a different pull request which I accidentally closed, Gavin wrote:

> I think a separate method called from ParseParameters and ReadConfigFile is the better way to go.

So that's what I've done here.