logwatch_7.4.1.bb: Bug fix

The "ln -sf ../..${datadir}/logwatch/scripts/logwatch.pl ${D}${sysconfdir}/cron.daily/0logwatch" is wrong.
it will lead to the logwatch unable to be used. so delete it.

Signed-off-by: Li Xin <lixin.fnst@cn.fujitsu.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>