Pull request with Russian translation update

[Geert Janssens]

We have received a pull request for an updated Russian translation [1].

The author is viktor811. However the last translator according to the current 
ru.po file is Dmitry Pavlov.

@Dmitry, if you are reading this:

- did viktor811 coordinate this with you ? If not I will ask him to do so.
- what do you want us to do with the PR? As my Russian knowledge is limited to 2 
words, I can't estimate the correctness of the translation.

Thanks for your feedback,

Geert


[1] https://github.com/Gnucash/gnucash/pull/80