[libvirt] Misc improvements to the storage driver

[Daniel P. Berrange]

This patch series started out as an attempt to fix the seriously
painful problem with iSCSI targets automatically logging in
whenever the network came online. In the process of fixing this
alot of other cruft is cleaned up

 docs/schemas/storagepool.rng          |    5 
 src/conf/storage_conf.c               |   21 +
 src/conf/storage_conf.h               |    1 
 src/storage/storage_backend.h         |    3 
 src/storage/storage_backend_fs.c      |   29 ++
 src/storage/storage_backend_iscsi.c   |  427 +++++++++++++++++++++++++---------
 src/storage/storage_backend_logical.c |   24 +
 src/storage/storage_backend_mpath.c   |   20 +
 src/storage/storage_backend_scsi.c    |   96 +++++++
 src/storage/storage_driver.c          |   65 +++--
 tools/virsh.c                         |   51 ++--
 11 files changed, 573 insertions(+), 169 deletions(-)

Daniel