Russian NLS Update: pg_dump

Hi,

Here is an updated version of translated pg_dump messages.
Changes are minor:

o One fuzzy translation fix
o Several typos and wordings fixed

I know that you guys are now in RC2 already, I just didn't
have my PC working to send these updates earlier. However,
I still hope this will get into 7.2 (it's not a code after all!)

Some other translators might want to fix fuzzy translations,
which have appeared not so long ago.

Regards,
Serguei

PS: Attached is entire po file, not a patch (it's just smaller).
PPS: I'll send similar fixes for the backend, because message
catalogs seem to have changed slightly.