Description of problem:
When statistics is toggled between "By Words" <-> "By Messages",
a spinner showed up to indicate that the statistics is being updated.

However, the spinner was still spinning even after the status is updated.

Version-Release number of selected component (if applicable):
Zanata 3.3.0-SNAPSHOT (20140217-0050)

How reproducible:
Always

Steps to Reproduce:
1. Go to any project, any version
   You should see a list of enabled languages.
2. Toggle the unit of statistics (either to By Messages or By Words)

Actual results:
The spinner was still spinning even the statistics has been updated.

Expected results:
The spinner should be removed after the statistics has been updated.

Additional info:
Click "Refresh" will remove the spinner. This can be temporary workaround.