Regenerate initrd after configuring keyboard (bnc#888804)

* Some autotranslated code polishing (in a different commit for easier review)
* Update dependency on yast2 >= 3.1.94 (new messages)
OK, when considering API. I think it should be quite small and now it contain unnecessary methods. I think it is enough if it contain these:
```
  different_root_path(directory, &block) # include allow_default_scr, stub_scr_write and include cleaning of written 
values
  stub_target_yast2 # only temporary workaround
  expect_to_execute
  written_value_for
```

usage of `different_root_path`:
```
around(:each) do |test|
  different_root_path("/tmp/root", &test)
end
```
see https://github.com/rspec/rspec-core/blob/master/lib/rspec/core/hooks.rb#L314