Many of the WWW are overwritten later which means the wrong value
is used. This did not happen before where the children were either
a) just using the pkg-descr from the parents
b) or had their own separate pkg-descr with custom WWW
Use WWW?= in parents when the child's WWW is different.
Children that use the same WWW as the parent can just inherit it,
i.e., the child WWW can be removed.
Approved by: portmgr (implicit)
