This is a cleanup patch for scsi_host removal.

- Addition of a shost_state member to the scsi_host strucuture to contain
"state" of the host instance.

- Added SHOST_ADD, SHOST_DEL, SHOST_CANCEL, SHOST_RECOVERY states for a scsi
host

- Addtion / rename of a new function scsi_host_cancel to cancel IOs in flight.

- Usage of the shost_state member to stop scsi_host_get's and calls to LLDD
queucommand under certain states.

- Reordered some of the scsi host sysfs unregistration.

 drivers/scsi/hosts.c       |   52 +++++++++++++++++++++++++--------------------
 drivers/scsi/scsi.c        |   37 ++++++++++++++++++++++++--------
 drivers/scsi/scsi_debug.c  |    5 ----
 drivers/scsi/scsi_error.c  |    7 ++----
 drivers/scsi/scsi_lib.c    |    5 ++--
 drivers/scsi/scsi_proc.c   |   12 +++++-----
 drivers/scsi/scsi_syms.c   |    2 -
 drivers/scsi/scsi_sysfs.c  |   43 ++++++++++++++++++++++++++-----------
 drivers/scsi/sg.c          |    3 +-
 include/scsi/scsi_device.h |    3 +-
 include/scsi/scsi_host.h   |   18 ++++++++++++---
 11 files changed, 121 insertions(+), 66 deletions(-)