This changes the raising of exceptions from:
  raise Exception, value
to
  raise Exception(value)

as the first form will be removed in python-3000 and the second form is
preferred now.

The changes also involve a few cases of changing from raising standard
exceptions and use our own ones.

The new version also fixes many pylint-generated warnings, especially in
ganeti-noded where I changed many methods to @staticmethod.

There is no functionality changed (barring any bugs).

This is only the backend part, from the command line the tags can't be
read/modified yet.

Reviewed-by: imsnah

Reviewed-by: iustinp

  - add an Update method on the ConfigWriter class;
  - make the AddInstance method not log disks for diskless types (helps with testing)
  - implement limited testing for the ConfigWriter with focus on the new Update method

Reviewed-by: iustinp

won't reread it if not modified by someone else.

Reviewed-by: iustinp

configuration.

Reviewed-by: imsnah

instead use an UUID prefix and a suffix denoting the disk iv_name
(sda/sdb) and possibly it's type (data/meta).

Reviewed-by: imsnah

Reviewed-by: iustinp

- Cleanup

Reviewed-by: iustinp

Reviewed-by: iustinp

Add warning about avoiding xm commands for instance creation
Also fix a man page reference in installing.sgml to use the docbook format

Reviewed-By: iustinp

Reviewed-by: iustinp

Reviewed-by: iustinp

Reviewed-by: iustinp

Refer to the glossary from the installing guide

Reviewed-By: iustinp

Reviewed-By: iustinp

Reviewed-By: iustinp, imsnah

Reviewed-by: iustinp

Reviewed-by: iustinp

Reviewed-by: iustinp

Reviewed-by: iustinp

Reviewed-by: iustinp

- Add the command to gnt-instance.sgml

Reviewed-by: iustinp

runnable on non-master nodes (and remove the list of instances and nodes
returned by it, that information can be retrieved by other opcodes).

Also, remove the node/instance list from "gnt-cluster info" as it
doesn't make sense to duplicate this information.

Reviewed-by: imsnah

Reason: if left ConfigWriter, nodes don't know to which cluster they belong.
This will bite us later when we'll revisit node join operation.

Cons: we lose the cluster name from the config file, which means a
standalone "cluster.data" is a little bit harder to analyze. But I have
a plan for this which will follow shortly.

Implementing this will also allow us to cleanly fix "gnt-cluster
getmaster".

Reviewed-by: imsnah

- Implement “gnt-instance reinstall”
- Fix two typos

Reviewed-by: iustinp

Reviewed-by: iustinp

Reviewed-by: iustinp

and all users have been converted, let's remove it from the slots of the
cluster object.

Also let's move the tcpudp_port_pool to the cluster object.

Reviewed-by: imsnah

Reviewed-by: iustinp

handling, as it can be static and outside of ganeti.

This also means we can get rid of a lot of infrastructure too:
  - the master/node config files checkers
  - one rpc function

- Split up info tests and add more of them
- Replace map() by [x for x in y]

Reviewed-by: iustinp

Reviewed-by: iustinp

Reviewed-by: imsnah

Reviewed-by: iustinp