Description of problem:
When I try to remove a package with yum with a broken install script
I am getting a python backtrace from yum.

Version-Release number of selected component (if applicable):
yum-3.2.21-9.fc11

How reproducible:
every time

Steps to Reproduce:
1. yum install ghc-HTTP
2. yum remove ghc
  
Actual results:
2.
=============================================================================================================================================================
 Package                             Arch                            Version                                      Repository                            Size
=============================================================================================================================================================
Removing:
 ghc                                 i386                            6.10.1-8.fc11                                installed                            178 M
Removing for dependencies:
 ghc-HTTP                            i386                            3001.1.5-1.fc11                              installed                            1.4 M

Transaction Summary
=============================================================================================================================================================
Install      0 Package(s)         
Update       0 Package(s)         
Remove       2 Package(s)         

Is this ok [y/N]: y
Downloading Packages:
Running rpm_check_debug
Running Transaction Test
Finished Transaction Test
Transaction Test Succeeded
Running Transaction
  Erasing        : ghc                                                                                                                                   1/2 
/usr/lib/ghc-6.10.1/HTTP-3001.1.5/unregister.sh: line 3: /usr/bin/ghc-pkg: そのようなファイルやディレクトリはありません
Traceback (most recent call last):
  File "/usr/lib/python2.6/site-packages/yum/rpmtrans.py", line 389, in callback
    self._scriptError(bytes, total, h)
  File "/usr/lib/python2.6/site-packages/yum/rpmtrans.py", line 509, in _scriptError
    (hdr, rpmloc) = h
ValueError: too many values to unpack
error: python callback <bound method RPMTransaction.callback of <yum.rpmtrans.RPMTransaction instance at 0x96f0d8c>> failed, aborting!


Expected results:
ghc-HTTP to be removed first and then ghc; no backtrace ;)

Additional info:
The removal order issue part looks very similar to bug 479257.