port downloads file when livecheck.check = moddate

[Ryan Schmidt]

For ImageMagick I had this livecheck defined:

livecheck.check     moddate
livecheck.url       ftp://ftp.imagemagick.net/pub/${name}/$ 
{name}.tar.bz2

When the portfile was up to date, "sudo port livecheck ImageMagick"  
returned quickly. However, when a new version of ImageMagick was  
available, that command took awhile, and I could see from my network  
traffic meter that it seemed to be downloading the entire archive  
before telling me the port was outdated.

Why is MacPorts downloading the file I specified, when I only wanted  
it to check its modification date -- a check which MacPorts is  
obviously already doing correctly, else if would be downloading the  
archive every time I check. But it's not; it's only downloading it  
when its modification date has in fact changed.