disk: add before_mount_dev() to mount_dev().
Merge branch 'feature-disk-before-mount-dev'
hypervisor,openvz: define before_mount_dev().
Merge branch 'feature-hypervisor-openvz-device'
hypervisor,openvz: make openvz-specific devices.
Merge branch 'feature-hypervisor-openvz-device'
hypervisor,openvz: make more openvz-specific devices.
Merge branch 'feature-hypervisor-openvz-device'
hypervisor,openvz: make loop device for openvz.
Merge branch 'feature-hypervisor-openvz-device'
disk: before_mount_dev -> after_umount_nonroot.
Merge branch 'feature-hypervisor-openvz-device'
Merge pull request #46 from hansode/master

after_umount_nonroot　hook