maint: Remove trailing spaces
Fix failing tests in netapp_export_spec

The netapp_export type defines a validation method that can raise an
ArgumentError if there is an invalid combination of property values.

But if such an error is raised puppet will actually handle it, add more
information about the error and then will then raise an
Puppet::ResourceError including the original error message. As a
result the spec tests did fail:

expected ArgumentError with message matching /Readonly and Readwrite
params cannot be the same./, got #<Puppet::ResourceError: Validation of
Netapp_export[/vol/volume] failed: Readonly and Readwrite params cannot
be the same.>

Expect the general Puppet::Error instead an ArgumentError
maint: Slightly refactor facts_spec

Instead of returning an NetApp::Facts object in the `facs` helper
function we can just return the facts hash. This not only reduces code
duplication but can also help when having multiple expectations about
facts. E.g. when writing a spec test like

    facts["foo"].should == "bar"
    facts.should have_key("awesome")

The retrieve method is only called once cause `let` only evaluates the
passed block once for each test.
Handle the fact that net-ifconfig-get is not available

In case the API call net-ifconfig-get is not available the API call
fails. As a result we should not expect to can access any child
elements.

Check the result of the net-ifconfig-get api call and skip the interface
facts if it the result is "failed".

The unit tests are suboptimal here because we don't test the positive
branch in case the api calls succeed. Unfortunately I don't have a
system available where the API calls works so I don't now how such an
answer would look like.
(#56) Updated facts tests to check for e0M interface and translation to
top-level facts.
Merge branch 'feature/pr56' into develop