Fix build after filemetadata move

- replace KIO_EXPORT with KDE4SUPPORT_EXPORT
- replace KIO_DEPRECATED with KDE4SUPPORT_EXPORT
- add strigi libs to linker if strigi is found

I *suppose* this is correct, since it looks logical (in fact like
omissions in CMakeLists.txt during the move. I'm pushing this because it
fixes the build, but it would certainly be good if someone else could
look over these changes.

CCMAIL:kde-frameworks-devel@kde.org