po/Makevars doc infelicities

[Karl Berry]

In gettext 0.14.5, the po/Makevars node in the manual says this:

    Only packages which have multiple `po/' directories at different
    locations need to adjust the three variables defined in `Makevars'.

1) there are more three variables in Makevars these days (happily).
2) there are reasons to adjust them other than multiple po directories.

Also, I wonder whether changes to Makevars variables are preserved
across gettextize updates.  Perhaps it could be mentioned here.

Also, the po/Makevars node ends with a paragraph about Rules-quot.  This
seems unrelated to Makevars to me, perhaps it could be included with the
other address@hidden stuff currently in the po/LINGUAS node.

Best,
Karl