Description of problem:
If yum is interrupted or dies before it can do the cleanup phase after the
package installations, it leaves duplicate entries in the rpm database that must
be cleaned manually with rpm -e

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


How reproducible:
Always.

run yum update, cause yum to die sometime during the middle of the operation. 
Packages that have not hit the cleanup stage have duplicates in the rpm
database.  For example, I did a yum update and in the middle of it, asked
gnome-terminal to open a new window. Instead gnome-terminal crashed, taking yum
with it.  This can cause the yum duplicate packages problem.  Or if you were
doing yum update over an ssh connection and lost the connection midway through
the yum update.  Happens more often than I'd like to admit.

Steps to Reproduce:
1. run yum update
2. yum dies in the middle (killed or controlling terminal crashes)
3. rpm -qa  and notice duplicates
  
Actual results:
duplicate packages

Expected results:
well, frankly I expect this result.  The problem is how to either prevent it
from happening or provide a tool to cleanup later.

Additional info:
Perhaps yum needs a commandline option to go back and make sure all the cleanup
has been done from the last yum run.