Mimesis: Generic providers do not work

[lk-geimfari]

It's always return data in English. Looks like someone created wrong PR, Travis CI passed it and i merge this PR.

I found issue. It's returns providers without locale:

https://github.com/lk-geimfari/mimesis/blob/99dfd8275bd212ea2651afb95d843818ec81c15d/mimesis/providers/generic.py#L46

@Valerievich we need to fix it and your help will very handy.

[sobolevn]

Regression test will also be very nice.

[Valerievich]

I'll try to fix it today.

[lk-geimfari]

@Valerievich Thank you!

[Valerievich]

I can't understand how to fix this issue by new PL if my previous PL #200 isn't merged yet. All changes in my fork master branch.
All I did to fix this issue is:

return attribute(self.locale)

I checked all 'locales' through Generic(). It works well.

[lk-geimfari]

@Valerievich I have merged your PR. Thank you!