Update translators and rename the file

Hello fellen,

Thank you for your adaptations, a few notes: the Evgeny Zhulin is not a translator, he simply communicated the translation of Anton Tarasov. I have replaced the Translator. If the Evgeny should later take part in the translation, we can add he in the list.

In addition, I corrected the filename: 
guide/ru/gnucash-guide-de.omf => guide/ru/gnucash-guide-ru.omf

Regards, 
DiMan

guide/ru/gnucash-guide-de.omf → guide/ru/gnucash-guide-ru.omf

@@ -389,7 +389,7 @@
       Dmitriy Mangul
     </contributor>
     <contributor>
-      Evgeny Zhulin 
+      Anton Tarasov
     </contributor>
     <title>
       Практическое руководство по GnuCash