Added option to disable ELB AZ unregister
Added option to disable ELB AZ unregister

sharabash/vagrant-aws,methodfactory/vagrant-aws,uber/vagrant-aws,KariusDx/vagrant-aws,mkubenka/vagrant-aws,sharabash/vagrant-aws,KariusDx/vagrant-aws,mkubenka/vagrant-aws,sneal/vagrant-aws,rtyler/vagrant-aws,uber/vagrant-aws,methodfactory/vagrant-aws,mitchellh/vagrant-aws,mitchellh/vagrant-aws,aaam/vagrant-aws,sneal/vagrant-aws,rtyler/vagrant-aws,aaam/vagrant-aws