Update descriptions of Cargo.toml.
Update descriptions of Cargo.toml.

hyunsik/hdfs-rs,fiji-flo/hdfs-rs,iron-kernel/hdfs-rs,hyunsik/hdfs-rs,iron-kernel/hdfs-rs,hyunsik/hdfs-rs,fiji-flo/hdfs-rs,iron-kernel/hdfs-rs,fiji-flo/hdfs-rs