This patch changes how list of tokens returned from the storage_service
API.
Instead of create a vector and construct a json object of it, use the
streaming capabilities of the http.
This is important for large cluster and prevent large allocations.
Fixes#3701
Signed-off-by: Amnon Heiman <amnon@scylladb.com>
Message-Id: <20180820195631.26792-1-amnon@scylladb.com>