There are still issues, especially with "gnt-instance modify" and
resetting values. However, this is a start.

Reviewed-by: ultrotter

We no longer use YAML in Ganeti at all. This patch converts the QA
configuration from YAML to JSON. JSON doesn't support comments and
I had to use a hack with fields starting with '#'.

Reviewed-by: ultrotter

This patch removes the options that allow to create local_raid1 or
remote_raid1 instances. It also modifies the documentation and removes
these disk templates from burnin and from qa.

Reviewed-by: imsnah

Reviewed-by: iustinp

Reviewed-by: iustinp

Reviewed-by: schreiberal

Reviewed-by: iustinp