Description of problem:
Got call trace when executing an invalid command when target targetcli from a python script.

Traceback (most recent call last):
  File "/usr/bin/targetcli", line 90, in <module>
    main()
  File "/usr/bin/targetcli", line 73, 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 899, in _execute_command
    self.log.error(msg)
  File "/usr/lib/python2.6/site-packages/configshell/log.py", line 159, in error
    self._log('error', msg)
  File "/usr/lib/python2.6/site-packages/configshell/log.py", line 112, in _log
    self.con.display(msg)
  File "/usr/lib/python2.6/site-packages/configshell/console.py", line 151, in display
    self.raw_write(text)
  File "/usr/lib/python2.6/site-packages/configshell/console.py", line 139, in raw_write
    self._stdout.write(text)
TypeError: argument 1 must be string or read-only character buffer, not exceptions.ValueError


Version-Release number of selected component (if applicable):
fcoe-target-utils-2.0rc1.fb16-6.el6.noarch

How reproducible:
100%

Steps to Reproduce:
1.Run the following script
# python
>>> import subprocess
>>> p=subprocess.Popen("targetcli /tcm_fc/10:00:5c:b9:01:c1:ec:75/ ls", stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True)
>>> stdout, stderr = p.communicate()
>>> print stderr


####### 

I do not see the call trace if I run the command directly from shell.
# targetcli /tcm_fc/10:00:5c:b9:01:c1:ec:75/ ls
No such path /tcm_fc/10:00:5c:b9:01:c1:ec:75