*_volume().
Added a "volumeName" parameter to the fs_initialize_volume() call.
Introduced a "flags" field to the fs_unmount_volume() call - I have only
defined one flag, B_FORCE_UNMOUNT, right now.
But the unmount behaviour should be discussed anyway first (always force
unmount?).
git-svn-id: file:///srv/svn/repos/haiku/trunk/current@2828 a95241bf-73f2-0310-859d-f6bbb57e9c96