some string issues in coreutils-9.4.170-7b206

[Wenbin Lv]

Hi,

I just finished updating the zh_CN translation for 9.4.170-7b206. Below are
some string related issues I have noticed:

src/chown-core.h:101: "owner and/or "should be translatable;
src/chown.c:84: "[OWNER][:[GROUP]]" and "GROUP" should be translatable;
src/copy.c:2731: "renamed %s -> %s" should be translatable, applying _() to
the whole ternary operator is not working;
src/cp.c:198: typo, "existing"

Thanks,
Wenbin Lv