Description of problem:

yumdownloader isn't able to find RPMS or SRPMS in channels that are configured
using mirror lists.

The URLs it returns are not valid paths to the RPMs in question; it appears to
be dropping the last path element of the mirror URL each time.

Version-Release number of selected component (if applicable):

yum-utils-1.0.3-1.fc6
(I think this bug also affects the FC7 version)

How reproducible:

Always

Steps to Reproduce:
1. yumdownloader --enablerepo=updates --urls kernel
2.
3.
  
Actual results:

Should generate the correct URL!

In this case, the value returned is (for this spin of the mirrors)

 
ftp://mirror.colorado.edu/pub/fedora/linux/core/updates/6/kernel-2.6.22.5-49.fc6.x86_64.rpm

the correct result should be

 
ftp://mirror.colorado.edu/pub/fedora/linux/core/updates/6/x86_64/kernel-2.6.22.5-49.fc6.x86_64.rpm

Expected results:


Additional info:

I think the culprit (or one of the culprits) is the 'urlparse.urljoin' line on
169 of /usr/bin/yumdownloader.  Note that 'urlparse.urljoin' works differently
from 'os.path.join'.  The left-hand argument is *not* assumed to be a directory
path unless it's terminated with a slash character:

  >>> import urlparse
  >>> urlparse.urljoin("a/b", "c")
  'a/c'
  >>> urlparse.urljoin("a/b/", "c")
  'a/b/c'