Update vendored Cortex. (#213)

Gopkg.lock

Gopkg.toml

...com/cortexproject/cortex/pkg/chunk/aws/aws_autoscaling.go

...exproject/cortex/pkg/chunk/aws/dynamodb_storage_client.go

...rtexproject/cortex/pkg/chunk/aws/dynamodb_table_client.go

...github.com/cortexproject/cortex/pkg/chunk/aws/fixtures.go

vendor/github.com/cortexproject/cortex/pkg/chunk/aws/mock.go

...m/cortexproject/cortex/pkg/chunk/aws/s3_storage_client.go

...ub.com/cortexproject/cortex/pkg/chunk/cache/background.go

.../github.com/cortexproject/cortex/pkg/chunk/cache/cache.go

...hub.com/cortexproject/cortex/pkg/chunk/cache/diskcache.go

...ub.com/cortexproject/cortex/pkg/chunk/cache/fifo_cache.go

....com/cortexproject/cortex/pkg/chunk/cache/instrumented.go

...hub.com/cortexproject/cortex/pkg/chunk/cache/memcached.go

.../cortexproject/cortex/pkg/chunk/cache/memcached_client.go

....com/cortexproject/cortex/pkg/chunk/cassandra/fixtures.go

.../cortexproject/cortex/pkg/chunk/cassandra/table_client.go

.../github.com/cortexproject/cortex/pkg/chunk/chunk_store.go

...ub.com/cortexproject/cortex/pkg/chunk/encoding/factory.go

...rtexproject/cortex/pkg/chunk/gcp/bigtable_index_client.go