clustershell was updated to upstream release 1.9:

* clush: add --mode support with sudo and sshpass examples
* clush: add options '--outdir=OUTDIR' and '--errdir=ERRDIR'
* clush: always close stdin stream of worker when it is not used
* clush: use daemon attribute instead of deprecated setDaemon()
* slurm.conf.example: filter out more Slurm node state flags
* NodeSet: add special notation @@source to expand group names
* RangeSet: nD folding optimization
* RangeSet: support ranges with zero padding of mixed lengths
* RangeSet: add explicit intiter() method to iterate over integers
* EngineClient: EnginePort improvements, add event ev_port_start()
* Tree: fix start and bufferize early writes
* Tree: fix error with intermediate gateways
* Defaults: Introduce CLUSTERSHELL_CFGDIR
* Worker: deprecate old EventHandler method signatures
* Worker: remove old last_*() methods