Add a MIN_CONFIG_TYPE that can be set to 'test' or 'boot'. The default
is 'boot' which is what make_min_config has done previously: makes a
config file that is the minimum needed to boot the target.

But when MIN_CONFIG_TYPE is set to 'test', not only must the target
boot, but it must also successfully run the TEST. This allows the
creation of a config file that is the minimum to boot and also
perform ssh to the target, or anything else a developer wants.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>