Remove expect in config

Then timeout reach observer process crash with message:
 
`thread '<unnamed>' panicked at 'Failed to fetch metadata: KafkaError (Metadata fetch error: OperationTimedOut (Local: Timed out))', /root/.cargo/registry/src/github.com-1ecc6299db9ec823/kafka-replicator-0.5.0/src/config.rs:508:34
`