Fix QFontConfigDatabase crash

Take into account the possibility that the target platform plugin does not
support platform services.

Change-Id: I48e7fac2e1230a9a7d450414044d23ed26b334be
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>
QLocale: cache the C locale's private

Change-Id: I81bbfeffebb5b7fc29d67bb7127beaf13838ac9f
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
QLocale: cache the QLocalePrivate for the default QLocale

Change-Id: I6f05da4d426a0aa685dd9f2fd0020e413a4bebad
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Merge branch 'stable' of git://qt.gitorious.org/qt/qtbase into st