def ssh_options(opts={})
      return @ssh_options if @ssh_options && opts.empty?
      ssh_opts = {"-i" => keypair.full_filepath,
           "-o" =>"StrictHostKeyChecking=no",
           }.merge(opts)
      @ssh_options = ssh_opts.collect{ |k,v| "#{k} #{v}"}.join(' ')
    end
def ssh_options(opts={})
      return @ssh_options if @ssh_options && opts.empty?
      ssh_opts = {"-i" => keypair.full_filepath,
           "-o" =>"StrictHostKeyChecking=no",
           }.merge(opts)
      @ssh_options = ssh_opts.collect{ |k,v| "#{k} #{v}"}.join(' ')
    end
Take a hash of options and join them into a string, combined with default options.
 Default options are -o StrictHostKeyChecking=no -i keypair.full_filepath -l user
 {'-i'=>'keyfile, '-l' => 'fred' } would become
 "-i keyfile -o StrictHostKeyChecking=no -i keypair.to_s -l fred"