Description of problem:
unregister CDS with rhui-manager doesn't release the CDS instance in first
attempt. When we list the cds instances after deletion, its still showing the
deleted instance in the list.

Version-Release number of selected component (if applicable):
pulp 0.166
rhui tools : 2.0.14

How reproducible:
Always

Steps to Reproduce:

rhui (cds) => l

-= RHUI Content Delivery Servers =-

  cds 01

------------------------------------------------------------------------------
rhui (cds) => d

Select the CDS instances to be removed from the RHUI: 
  -  1 : cds 01
Enter value from (1-1) to toggle selection, 'c' to confirm selections, or '?'
for more commands: 1

Select the CDS instances to be removed from the RHUI: 
  x  1 : cds 01
Enter value from (1-1) to toggle selection, 'c' to confirm selections, or '?'
for more commands: c


The following CDS instances will be unregistered:
  cds 01
Proceed? (y/n) y


Unregistering cds 01...

------------------------------------------------------------------------------
rhui (cds) => l

-= RHUI Content Delivery Servers =-

  cds 01


Actual results:

rhui (cds) => l

-= RHUI Content Delivery Servers =-

  cds 01
-------------------

[root@pulp-server ~]# pulp-admin -u admin -p admin cds list
+------------------------------------------+
                CDS Instances
+------------------------------------------+

Name                 cds.pnq.redhat.com       
Hostname             cds 01                   
Description          None                     
Repos                None                     
Last Sync            Never                    
Status:
   Responding        No                       
   Last Heartbeat    2011-04-18 14:11:31      



Expected results:
CDS instance should be released.

Additional info:
Note: when you will unregister the same cds instance in second attempt, it will
be released successfully.

Result in second attempt:
===========================

The following CDS instances will be unregistered:
  cds 01
Proceed? (y/n) y

Unregistering cds 01...

------------------------------------------------------------------------------
rhui (cds) => l

-= RHUI Content Delivery Servers =-

No CDS instances are registered.