Bug 12706: Remove CGI::scrolling_list from serial_stats.pl

Bug 12706: Remove CGI::scrolling_list from serial_stats.pl

This patch depends on Bug 12696

Removed one instance in this file.
Pulldown with one value, 'CSV'

To test:
1. Apply the patch for Bug 12696
2. Apply this patch
3. Go to Reports > Statistics wizard > Serial
4. Check 'Into an application' pulldown, with value 'CSV'
5. Search for regressions

Followed test plan. Patch behaves as expected.
Signed-off-by: Marc Véron <veron@veron.ch>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Passes tests and QA script, works as described.

Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>