Description of problem:
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When rebalance is started on a volume, the Rebalance -> Start button remains enabled for a while, but the task starts appearing in the Tasks tab at the bottom of the page.

Either the button should be disabled once rebalance is started, or the task should appear only once the rebalance is truly started (i.e. when the Start button is disabled)

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. Start rebalance on a volume from the Console.

Actual results:
The Rebalance -> Start button remains active for a while but the tasks appears at the bottom.

Expected results:
Either the button should be disabled once rebalance is started, or the task should appear only once the rebalance is truly started (i.e. when the Start button is disabled)

Additional info: