Today's fresh f20 installation:

[root@dhcp-25-70 ~]# virt-manager 
Traceback (most recent call last):
  File "/usr/share/virt-manager/virt-manager", line 277, in <module>
    main()
  File "/usr/share/virt-manager/virt-manager", line 177, in main
    virtinstcli.setupLogging("virt-manager", options.debug, False, False)
  File "/usr/share/virt-manager/virtinst/cli.py", line 158, in setupLogging
    os.mkdir(vi_dir, 0751)
OSError: [Errno 2] No such file or directory: '/root/.cache/virt-manager'
[root@dhcp-25-70 ~]# mkdir -p /root/.cache/virt-manager
[root@dhcp-25-70 ~]# virt-manager 
[root@dhcp-25-70 ~]# echo $?
0
[root@dhcp-25-70 ~]# rpm -q virt-manager
virt-manager-0.10.0-4.git79196cdf.fc20.noarch