tmf: Correct the statistics partial event count

tmf: Correct the statistics partial event count

Fixes bug 387838

Reload correctly the partial event count in the statistics view when an
experiment is reselected during its indexing.

Change-Id: I1f5aaf7d54812ba2f934e173df5268c7eb24e869
Signed-off-by: Mathieu Denis <mathieu.denis@polymtl.ca>
Reviewed-on: https://git.eclipse.org/r/7357
Reviewed-by: Bernd Hufmann <bhufmann@gmail.com>
IP-Clean: Bernd Hufmann <bhufmann@gmail.com>
Tested-by: Bernd Hufmann <bhufmann@gmail.com>
Reviewed-by: Alexandre Montplaisir <alexmonthy@voxpopuli.im>
IP-Clean: Alexandre Montplaisir <alexmonthy@voxpopuli.im>
Tested-by: Alexandre Montplaisir <alexmonthy@voxpopuli.im>