Fluentd config: simplify buffer variables
Fluentd config: simplify buffer variables

Signed-off-by: Christian Berg <2c193f2cde837e19446ecde8442b1b6ec94be9a1@zalando.de>

zalando-incubator/kubernetes-on-aws,zalando-incubator/kubernetes-on-aws,zalando-incubator/kubernetes-on-aws