Fix error at pl translation

[nmaletm]

I did a mistake at the PL translation, and there were some words that make the translation invalid.

I know that this is not the place but, I want to also notice you that I've made a new pod from the fork. I've added iOS8 information. You can see it here https://github.com/nmaletm/STNotificationHelper. I've added your name as an Author, and at the beginning is explained that the origin is your pod.