Description of problem:
It seems fix for bug 828681 broke targetcli create.

Version-Release number of selected component (if applicable):
fcoe-target-utils-2.0rc1.fb16-1.el6.noarch

How reproducible:
always

Steps to Reproduce:
1. service fcoe-target start
2. targetcli /backstores/fileio create disk /tmp/test 10M
  
Actual results:
Using params size=10M write_back=True sparse=True
Traceback (most recent call last):
  File "/usr/bin/targetcli", line 91, in <module>
    main()
  File "/usr/bin/targetcli", line 74, in main
    shell.run_cmdline(" ".join(sys.argv[1:]))
  File "/usr/lib/python2.6/site-packages/configshell/shell.py", line 934, in run_cmdline
    self._execute_command(path, command, pparams, kparams)
  File "/usr/lib/python2.6/site-packages/configshell/shell.py", line 909, in _execute_command
    result = target.execute_command(command, pparams, kparams)
  File "/usr/lib/python2.6/site-packages/targetcli/ui_node.py", line 84, in execute_command
    pparams, kparams)
  File "/usr/lib/python2.6/site-packages/configshell/node.py", line 1405, in execute_command
    result = method(*pparams, **kparams)
  File "/usr/lib/python2.6/site-packages/targetcli/ui_backstore.py", line 314, in ui_command_create
    write_back=write_back)
TypeError: __init__() got an unexpected keyword argument 'write_back'

Expected results:
Using buffered mode.
Created fileio disk with size 10M
Entering new node /backstores/fileio/disk

Additional info:
This works fine in fcoe-target-utils-2.0rc1.fb10-5.el6.noarch, possibly a regression.