Description of problem:
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When the user tries to start rebalance on a volume from the Console, such that it rebalance was already started on that volume from the gluster CLI, does not result in an error pop-up.

The events log shows the following message - 

Could not start Gluster Volume <vol_name> rebalance.

The tasks tab shows the failure as follows - 

Rebalancing Gluster Volume dis_vol in Cluster test.( STARTED  )
 
The 'STARTED' enclosed in brackets should be replaced by something like 'IN PROGRESS', which better conveys the message.

Version-Release number of selected component (if applicable):
oVirt Engine Version: 3.4.0-0.2.master.20130911113322.gite7ade4a.fc19 

How reproducible:
Always

Steps to Reproduce:
1. Create a volume of type distribute or distributed-replicate, start it and
mount the volume on a client. 
2. Create some data on the mount point.
3. Add a brick (or a pair of bricks, depending on whether the volume is pure-distribute or distributed-replicate) and start rebalance on the volume from gluster CLI
4. From the Console, select the volume and click on Rebalance -> Start

Actual results:
Rebalance fails to start which is displayed as a message in the events log.

Expected results:
An error pop-up should be displayed to the user explaining the reason for failure. 

Additional info: