fix current rubocop issues

[bastelfreak]

Right now there is a bit of rubocop foo:

$ bundle exec rubocop -c .rubocop.yml -D -S -a
Inspecting 26 files
............CC...C........

Offenses:

spec/unit/type/network_config_spec.rb:29:14: C: RSpec/DescribeSymbol: Avoid describing symbols.
    describe :name do
             ^^^^^
spec/unit/type/network_config_spec.rb:33:14: C: RSpec/DescribeSymbol: Avoid describing symbols.
    describe :reconfigure do
             ^^^^^^^^^^^^
spec/unit/type/network_route_spec.rb:15:14: C: RSpec/DescribeSymbol: Avoid describing symbols.
    describe :name do
             ^^^^^
spec/unit/provider/network_config/interfaces_spec.rb:260:5: C: RSpec/ScatteredLet: Group all let/let! blocks in the example group together.
    let(:content) { described_class.format_file('', [lo_provider, eth0_provider, eth1_provider]) }
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

26 files inspected, 4 offenses detected

They are currently disabled, but should be fixed.