Don't try to fix strings with escaped bytes

While QString::fromUtf8("ö") is equal to QString::fromUtf8("\xc3\xb6"),
QStringLiteral("ö") is not equal to QStringLiteral("\xc3\xb6") because the
escaped bytes won't be converted to utf-16 but instead used directly as is.

CCMAIL: faure@kde.org
CCMAIL: montel@kde.org