PostgreSQL web ftp browser symlink fix

I've just committed a fix to the PostgreSQL website ftp browser to fix handling of symbolic links in the ftp tree.

Previously, symbolic links were only read on creation of the browse pages. This made links to for example /ftp/win32 (which is a symbolic link to /ftp/binary/v8.0.3/win32) fail, since only the /ftp/index.html page was actually updated. Unfortunatly, just this link is present in the release notes for 8.0.3 - and was broken. Not good!

The new code generates Apache rewrite rules that does proper redirection of anything inside a symlinked directory.