Mock additional x-pack settings to avoid missing configuration errors (#211)

This commit mocks the additional x-pack settings to avoid missing configuration errors

Author: edmocosta

spec/filters/geoip_online_spec.rb

@@ -15,6 +15,8 @@
       dir_path = Stud::Temporary.directory
       File.open(dir_path + '/uuid', 'w') { |f| f.write(SecureRandom.uuid) }
       allow(LogStash::SETTINGS).to receive(:get).and_call_original
+      allow(LogStash::SETTINGS).to receive(:get).with("xpack.geoip.downloader.enabled").and_return(true)
+      allow(LogStash::SETTINGS).to receive(:get).with("xpack.geoip.download.endpoint").and_return(nil)
       allow(LogStash::SETTINGS).to receive(:get).with("path.data").and_return(dir_path)
     end