Only accept lower-case "true" and "false", as documented.
The old check didn't match either the documentation, nor the QSettings/
QVariant behavior (where, for a boolean value, any lower-cased content
that not empty, "0" or "false" is considered true).
Change-Id: I317d29c16a27f862001b9dff02e8298df8acf5a6
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>
b11adb825c