Strange things sometimes happen,one of them is a rpm database got corrupted . This means that the computer tells you something is installed and it really is not. i personally encountered this few times before and usually this happens when the ssh session/connection to the server cut off(i used to ssh to the server , and it is behind the vpn connection when i was doing yum update on server and when i re-login again to the server i just kill the yum right away 
, my bad, better to use screen )
, my bad, better to use screen )the symptom:
If rpm / yum command hangs during operations or you see error messages – it means your rpm database corrupted. just backup your current rpm database, remove it and rebuild it most likely will solve the problem
# rm -f /var/lib/rpm/__db*
# rpm –rebuilddb
# yum update
