[cjk] a couple of bit-rots in the cjk examples

[Hin-Tak Leung]

Hi Werner,

I noticed a bit of difficulties of running some of the cjk examples a while ago 
while looking at the cjk-enc.el issue, so I just revisited the examples.

In cjk/examples/CJKbabel.tex , both of the 'vietnam' references( one as option 
to the babel package, the other in \begin{otherlanguage}{vietnam} ) should now 
be "vietnamese" , with the 'ese' at the end.

I also encountered some difficulty with the cyrillic part of muletest - that it 
requires the lh fonts (and the associated metafont stuff) wasn't obvious. 
Somehow I already had greek, german and vietamese, but took a while to work 
that one out. TexLive is splitted into a fair number of optional components on 
fedora, and it isn't obvious which package I am missing; I did have 
language-cyrillic, but that's not enough, nor collection-fontsrecommended or 
collection-fontsextra . the lh fonts seems to be a loner.

I see some of the information is already in  cjk/doc/cjk-enc.txt , but it would 
be nice to put the actual font requirements, etc in the comments of individual 
examples.

Hin-Tak