78e8f1dca0
api_workers=0 does not disable api workers but neutron-server still launches one api worker. Rejecting 0 helps user notice that the value they request in config files is not honored. Also the other rpc workers options disable the corresponding workers completely by setting these options to 0, so setting negative values work but does not bring any special benefit. Change-Id: Iac16b241c71ac1068c6fbea3cc792b74bfc66c03