[Qt] MediaPlayerPrivateQt.cpp doesn't build in debug

Unreviewed build fix.

We need to include Logging.h to get the LOG definitions.

* platform/graphics/qt/MediaPlayerPrivateQt.cpp:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@148600 268f45cc-cd09-0410-ab3c-d52691b4dbfc