Description of problem:
When I push a package headers to satellite and then I want to re-push whole
file, I get 500: Internal Server Error.

How reproducible:
always

Steps to Reproduce:
1. rhnpush --server=xen34.englab.brq.redhat.com --username=admin
--password=admin --orgid=1 --channel=rhel-x86_64-as-4  --header
anacron-2.3-32.i386.rpm
2. rhnpush --server=xen34.englab.brq.redhat.com --username=admin
--password=admin --orgid=1 --channel=rhel-x86_64-as-4 anacron-2.3-32.i386.rpm
  
Actual results:
ERROR: unhandled exception occurred: (<ProtocolError for
xen34.englab.brq.redhat.com /APP: 500 Internal Server Error>).

Expected results:
Whole file is uploaded or relevant error message is printed.

Additional info:
Traceback (most recent call last):
  File "/usr/share/rhn/server/apacheRequest.py", line 108, in call_function
    response = apply(func, params)
  File "/usr/share/rhn/server/handlers/app/packages.py", line 415, in
getPackageMD5sumBySession
    return self._getPackageMD5sum(org_id, pkg_infos, info)
  File "/usr/share/rhn/server/handlers/app/packages.py", line 463, in
_getPackageMD5sum
    filePath = os.path.join(CFG.MOUNT_POINT, row['path'])
  File "/usr/lib64/python2.3/posixpath.py", line 60, in join
    if b.startswith('/'):
AttributeError: 'NoneType' object has no attribute 'startswith'

row['path'] should contain file path, but uploaded file doesn't exist on
satellite (there's only header in database), so variable contains None value.