EXCLUDE_SERVERS doesn't work with USE_SUBNETS

When we look for interfaces by CIDR and specify EXCLUDE_SERVERS we may result in:

2017-06-09 13:50:07::ERROR::run_setup::1027::root:: Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/packstack/installer/run_setup.py", line 1022, in main
    _main(options, confFile, logFile)
  File "/usr/lib/python2.7/site-packages/packstack/installer/run_setup.py", line 678, in _main
    runSequences()
  File "/usr/lib/python2.7/site-packages/packstack/installer/run_setup.py", line 645, in runSequences
    controller.runAllSequences()
  File "/usr/lib/python2.7/site-packages/packstack/installer/setup_controller.py", line 81, in runAllSequences
    sequence.run(config=self.CONF, messages=self.MESSAGES)
  File "/usr/lib/python2.7/site-packages/packstack/installer/core/sequences.py", line 109, in run
    step.run(config=config, messages=messages)
  File "/usr/lib/python2.7/site-packages/packstack/installer/core/sequences.py", line 50, in run
    self.function(config, messages)
  File "/usr/lib/python2.7/site-packages/packstack/plugins/neutron_350.py", line 682, in create_manifests
    n_host, config)
  File "/usr/lib/python2.7/site-packages/packstack/modules/common.py", line 66, in cidr_to_ifname
    info = config['HOST_DETAILS'][host]
KeyError: '10.94.4.132'

That's because host details dict doesn't contain excluded servers.