jenkins/ci.jpl: Add comment why stacktrace is not printed on exception

Also add commented out code to print the stacktrace, to not research it
next time from scratch (but again, it unlikely to be useful).

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Change-Id: Iebd9d54f05674bae2fa527a6cfa9311d33169761
1 file changed