Finalize support for multiple mirror types.

Finalize support for multiple mirror types.

Most of the support was there, but not actually a loop over what the
different mirror types... Also, add support for sync files not named
web_sync_timestamp, and hostnames other than www.postgresql.org :-)

In passing, fix http protocol error that we used "\n" instead of "\r\n" to
terminate lines, which seems to confuse lighttpd on the ftp mirrors...

git-svn-id: https://pgweb.postgresql.org/svn/trunk@2894 8f5c7a92-453e-0410-a47f-ad33c8a6b003