Explanation: since we use lists and not a string, every argument we give
is passed unchanged to the remote shell. So, for example, passing
'/etc/init.d/ganeti restart' to the remote shell, it will try to run the
path /etc/init.d/ganeti\ restart. With the s space included. This
breaks, for example, gnt-node add and gnt-cluster command.

The original problem with the backup routines that led to the "'" change
is that they use a plain " ".join(list), but we don't need to quote the
whole ssh remote command for this. We can simply use the existing
utils.ShellQuoteCmd(list) which does the proper quoting of the ';' or
'&&' metacharacters.

With this change, both gnt-node add, gnt-cluster command and
export/import work.

This also improves the error-handling behaviour of one cat command by
making it conditional on the preceding mkdir.

Reviewed-by: ultrotter

This avoids forgetting some parameters, as it's happening right now 
(the correct known host file is not being passed)

In order to do so we split SSHCall into an auxiliary BuildSSHCmd which builds
the command but doesn't actually call it, and SSHCall itself which runs RunCmd
on top of BuildSSHCmd's result. BuildSSHCmd is then explicitely called by 
import/export who has to build a more complex command to be run later.

This changes a ';' to '&&' to make sure we run the create script from
the correct directory.

Reviewed-by: imsnah

This changes:
  - cluster setup, we no longer edit /etc/ssh/ssh_known_hosts but our
    own file
  - node add, we no longer remove root's known_hosts (twice)
  - gnt-instance console, both the LU and the script: since now the ssh
    setup is not standard, we need to build the ssh cmdline in the LU
    (instead of manually building it in the script) with the correct
    parameters and use the command line as returned in the script
  - ssh.py, many changes, split options in module-level constants so
    that building the command line in different places is easier/more
    logical
  - backend.py, we no longer remove root's known_hosts in Add node, and
    we allow our own known_hosts file to be uploaded

Reviewed-by: imsnah

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).

Reviewed-by: iustinp

Reviewed-by: iustinp

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

- Create all --output options using a constant
- Put node checking code from opcodes into a single function
- Do the same for output fields

Reviewed-by: iustinp

  - move the master node name from the ConfigWriter to SimpleStore (all
    nodes need this, and it was the only thing pulled in from the
    ConfigWriter on nodes)
  - fix mcpu.py and the testing w.r.t. this change; for testing, rename
    the fake_config.py to mocks.py and add a FakeSStore object
  - then add a ganeti-master script which can be run on any node at boot
    and which will not do anything if not master on start (on stop it
    will still try to remove the ip address)
  - also add a new cluster-wide variable (master_netdev) that determines
    on which interface we add this ip address; it's customizable at
    cluster init time
  - also remove the cluster name file which was separately handled from
    ssconf (not needed anymore)
  - remove the master init.d links from the list of config files as this
    is not our responsibility now