Comment 5 for bug 876154

I added a bypass to that check (without changing line numbers, so this should be good for precise code):

02-22 15:30 DEBUG TaskList: New task check_iso
02-22 15:30 DEBUG TaskList: ### Running check_iso...
02-22 15:30 DEBUG CommonBackend: Checking C:\ubuntu\install\installation.iso
02-22 15:30 DEBUG Distro: checking Ubuntu ISO C:\ubuntu\install\installation.iso
02-22 15:30 DEBUG Distro: wrong size: 2095054848 > 900000000
02-22 15:30 DEBUG TaskList: ### Finished check_iso
02-22 15:30 ERROR TaskList: 'WindowsBackend' object has no attribute 'iso_path'
Traceback (most recent call last):
  File "\lib\wubi\backends\common\tasklist.py", line 197, in __call__
  File "\lib\wubi\backends\common\backend.py", line 593, in get_iso
  File "\lib\wubi\backends\common\backend.py", line 572, in use_iso
AttributeError: 'WindowsBackend' object has no attribute 'iso_path'
02-22 15:30 DEBUG TaskList: # Cancelling tasklist
02-22 15:30 DEBUG TaskList: # Finished tasklist
02-22 15:30 ERROR root: 'WindowsBackend' object has no attribute 'iso_path'
Traceback (most recent call last):
  File "\lib\wubi\application.py", line 58, in run
  File "\lib\wubi\application.py", line 130, in select_task
  File "\lib\wubi\application.py", line 205, in run_cd_menu
  File "\lib\wubi\application.py", line 120, in select_task
  File "\lib\wubi\application.py", line 158, in run_installer
  File "\lib\wubi\backends\common\tasklist.py", line 197, in __call__
  File "\lib\wubi\backends\common\backend.py", line 593, in get_iso
  File "\lib\wubi\backends\common\backend.py", line 572, in use_iso
AttributeError: 'WindowsBackend' object has no attribute 'iso_path'