Description of problem:
In the JBoss CLI when using tab completion, if the CLI presents the user with a choice of the next element, the CLI can "get stuck" if the user deletes [backspace] the command typed so far. If the user tries to exit, the CLI prints an error message.

Version-Release number of selected component (if applicable):
6.4.4

How reproducible:
yes

Steps to Reproduce:
1. Start JBoss in standalone
2. Start the CLI and connect
3. Type "/subsystem=security/security-domain="
4. Press [TAB]
5. Use the Backspace key to remove the text on the line
6. Type "exit" and press Enter
7. Error message is displayed


Actual results:

[standalone@localhost:9999 /] /subsystem=security/security-domain=  [TAB]
jboss-ejb-policy  jboss-web-policy  other             
[standalone@localhost:9999 /] /subsystem=security/security-domain=  [TAB]
jboss-ejb-policy  jboss-web-policy  other             
[standalone@localhost:9999 /]      [BACKSPACE TO CLEAR ALL TEXT] [ENTER]
[standalone@localhost:9999 /] exit
Node type is not complete at index 0
[standalone@localhost:9999 /] 


Expected results:
exit command is successful when typed as described above.