HYD-511: FlmsDrain does not cope with removed targets/hosts
HYD-511: FlmsDrain does not cope with removed targets/hosts

It does now.  Logs a warning and discards stats associated
with deleted entities.

Change-Id: I2da5dec86d53538faa25a7e47ac2d4806d330acd

intel-hpdd/intel-manager-for-lustre,intel-hpdd/intel-manager-for-lustre,intel-hpdd/intel-manager-for-lustre