Meta server: implement read dir plus variants to always omit last chunk info, and report only file id (i-node number), name, and type. The later variant can be used with "glob" or recursive removal, for example, and can reduce meta server network bandwidth and cpu utilization.
Client library: use new read dir plus RPCs variants, extent kfs client api to allow to specify read dir plus flags. Use read dir plus variant that report only file id / i-node and type with recursive directory removal, and kfs glob, to reduce meta server and client cpu and bandwidth.