Description of problem:

When I add external event with bad severity input I get  "General command validation failure" . When I don't pass flood_rate I get Internal Engine Error. 
I would expect to get more informative error message . 



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


How reproducible:


Steps to Reproduce:
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Actual results:


Expected results:


Additional info:


## bad severity input 

[RHEVM shell (connected)]# add event --custom_id 123 --origin "newvirt" --severity "high" --description "test" --flood_rate 30

error: 
status: 400
reason: Bad Request
detail: General command validation failure.


## flood rate is not passed 


[RHEVM shell (connected)]# add event --custom_id 123 --origin "newvirt" --severity "error" --description "test" --flood_rate 

error: 
status: 400
reason: Bad Request
detail: Internal Engine Error



[RHEVM shell (connected)]# 
[RHEVM shell (connected)]# 
[RHEVM shell (connected)]# 
[RHEVM shell (connected)]# 
[RHEVM shell (connected)]# 
[RHEVM shell (connected)]# 
[RHEVM shell (connected)]# add event --custom_id 123 --origin "newvirt" --severity "error" --description "test" --flood_rate 30

id         : 41662
description: test
code       : 9803
custom_id  : 123
flood_rate : 30
origin     : newvirt
severity   : error
time       : 2013-04-08T16:07:47.937+03:00