vietnamese/vietunicode-*: Fix options (3 ports)

The -hannom, -web1, and -trichlor ports all had their options mis-set
by the unnecessary use of <pre> and <post>. They sandwhiched a third
makefile that pulled in <options> which is sufficient. Remove <pre>
and <post> inclusions to restore option functionality of these ports.
Bump to be on the safe side.