Add workaround for case-changing renaming of files on Linux/FAT32.

The underlying rename() of the operating system simply does
nothing when renaming 'foo' to 'Foo' in a case insensitive file
system. Work around by moving in 2 steps.

Change-Id: Ibc73724bfca402a5ce7fcf2a83e8fea32ff71093
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: David Faure (KDE) <faure@kde.org>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>