update typesafe config 1.2.1

akka 2.3.3 depends on typesafe config 1.2.1 https://github.com/akka/akka/blob/v2.3.3/project/AkkaBuild.scala#L1146
I think we should use same version
Merge pull request #2972 from xuwei-k/update-typesafe-config

update typesafe config 1.2.1