sla_xml have to be passed always. As this test have to work on low level API
it is required to follow such API.

It supports cases when Person is in middle of requesting of Software
Instance.

User cannot fetch his instance until related sale order is not confirmed.

brctl is the only command which remains mandatory (except if alter_network
is false), as it is used to fetch information from system that even an
unprivileged user can see.

Example use:
PATH=$PATH:/usr/sbin ./bin/slapformat -cdv slapos.cfg

Prepares for incomming monkey-patching.

Output system commands and system-altering functions from python's os
module.

SLA XML is stored on Software Instance, but in many place the dictionary have
to be used.

It will be later used to follow SLA.

Later is shall be used in order to being followed.

It is easier to store on higher level, as pure XML. Other methods will have to
unserialise data from XML, which would be needed anyway in case of storing
them this way.

This reverts commit 79f0aaea.

More code analysis is required in order to being able support required cases
with parameters passed by user.

SlapTool itself shall not force to pass all possible parameters, as slap
library calls it in different ways.

Add support for lack of existence of computer_id and computer_partition_id,
in this case assume that human (person) is logged in by slap library.

Person does not have to be validated to be loggable user,
but Computer or Software Instance validation state is important,
so split to two queries.

Note: No typo in exception.