Description of problem:

I had a crash in the middle of a yum uprgade and ended up with a bunch of partially installed packages that yum believe were fully installed. So I tried running yum verify to check for missing files - yum verify ran for a while and then exited with an exception (see below)

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

$ yum info yum-plugin-verify
Loaded plugins: langpacks, presto, refresh-packagekit, verify
Installed Packages
Name        : yum-plugin-verify
Arch        : noarch
Version     : 1.1.31
Release     : 2.fc16
Size        : 49 k
Repo        : installed
From repo   : fedora

Actual results:

$ yum verify
Loaded plugins: langpacks, presto, refresh-packagekit, verify
==================== Installed Packages ====================
NetworkManager.x86_64 : Network connection manager and user applications
    File: /var/run/NetworkManager
        Problem:  file is missing

at.x86_64 : Job spooling tools
    File: /var/spool/at/spool
        Problem:  file is missing (Permission denied)

audit.x86_64 : User space tools for 2.6 kernel auditing
    File: /etc/audisp/plugins.d
        Problem:  file is missing (Permission denied)
    File: /lib/systemd/system/auditd.service
        Problem:  checksum does not match
        Current:  sha256:e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
        Original: sha256:a36ae19a9c1328747a91f565bca312a26bc61eab89ea27ec56053bb99049a437
                                   --------                                   
        Problem:  size does not match
        Current:    0  
        Original: 196  
    File: /sbin/audispd
        Problem:  checksum does not match
Traceback (most recent call last):
  File "/usr/bin/yum", line 29, in <module>
    yummain.user_main(sys.argv[1:], exit_code=True)
  File "/usr/share/yum-cli/yummain.py", line 309, in user_main
    errcode = main(args)
  File "/usr/share/yum-cli/yummain.py", line 140, in main
    result, resultmsgs = base.doCommands()
  File "/usr/share/yum-cli/cli.py", line 462, in doCommands
    return self.yum_cli_commands[self.basecmd].doCommand(self, self.basecmd, self.extcmds)
  File "/usr/lib/yum-plugins/verify.py", line 363, in doCommand
    self.show_data(base, msg, ypl.installed, 'Installed Packages')
  File "/usr/lib/yum-plugins/verify.py", line 316, in show_data
    self.show_problem(base, msg, problem, done_prob)
  File "/usr/lib/yum-plugins/verify.py", line 284, in show_problem
    msg("        Current:  " + hib + cv + hie)
TypeError: cannot concatenate 'str' and 'NoneType' objects