Description of problem:
Internal engine error when adding new host with already exist name

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


How reproducible:
100%

Steps to Reproduce:
1. create host named "aa"
2. create another host named "aa"
3.
  
Actual results:
UI - dialog with "Error while executing action New Host: Internal Engine Error" is shown
backend - sql exception:
2013-01-08 17:09:09,040 ERROR [org.ovirt.engine.core.bll.AddVdsCommand] (http--0.0.0.0-8700-5) [6159c275] Command org.ovirt.engine.core.bll.AddVdsCommand throw exception: org.springframework.dao.DuplicateKeyException: CallableStatementCallback; SQL [{call insertvdsstatic(?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)}]; ERROR: duplicate key value violates unique constraint "vds_static_vds_name_unique"

Expected results:
no exception in the backend, better error in the UI

Additional info:
we found that in v3.0 we couldn't get into this scenario because the UI prevented the user from specifying an already exist name for new VM. the solution here should be in the backend also because of rest api.