variables. The underline is there to mark it as a private module.

Reviewed-by: iustinp

- Bump version number to 1.2b2
- Add version.py file generated from version.py.in by autoconf

Reviewed-by: schreiberal

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

Reviewed-by: imsnah

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

Reviewed-by: imsnah

  - 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