filesink: Fix Windows build by using _commit instead of fsync.
filesink: Fix Windows build by using _commit instead of fsync.

centricular/gstreamer,jpxiong/gstreamer,centricular/gstreamer,krichter722/gstreamer,shelsonjava/gstreamer,StreamUtils/gstreamer,jpxiong/gstreamer,shelsonjava/gstreamer,StreamUtils/gstreamer,krichter722/gstreamer,krichter722/gstreamer,centricular/gstreamer,shelsonjava/gstreamer,jpxiong/gstreamer,centricular/gstreamer,jpxiong/gstreamer,StreamUtils/gstreamer,shelsonjava/gstreamer,shelsonjava/gstreamer,StreamUtils/gstreamer,krichter722/gstreamer,centricular/gstreamer,krichter722/gstreamer,StreamUtils/gstreamer,jpxiong/gstreamer