[lmi] Resetting hard-coded defaults before loading 'configurable_settings.xml'

[Greg Chicares]

Evgeniy--In 'gnome-xml-branch',
configurable_settings::load_from_file() has a section that
begins with this comment:

    // first of all reset all members to default values

I understand what it does, but would like to understand why.
What problem would occur if we didn't do this?