* Unmount when uninitializing a partition.
* Finished the media checker implementation, i.e. we rescan when a media
was inserted and uninitialize when ejected.
* Turned the disk device media checker from a kernel daemon into a thread.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@22909 a95241bf-73f2-0310-859d-f6bbb57e9c96