Description of problem:
yumdownloader doesn't check if rpms exists anymore. So it overwrites already
existing rpms. In further versions (eg. the one from fc6) it then shows a line
like this:
"./rpm-4.4.2-33.fc6.i386.rpm already exists and appears to be complete"


Version-Release number of selected component (if applicable):
yum-utils-1.1.3-1.fc7


How reproducible:


Steps to Reproduce:
1. yum install yum-utils
2. yumdownloader rpm
3. yumdownloader rpm
  
Actual results:
Both times the package "rpm" is downloaded by yumdownloader


Expected results:
yumdownloader only should download the package once. The second time it should
show a message that it is already downloaded.

Additional info: