Generate non-preferred APIs by default

Warn instead of failing on Discovery URL requests that error. Some
URLs on the Discovery index return 404s, so skipping them saves trouble.

bin/generate-api

@@ -28,7 +28,6 @@ module Google
     desc 'gen OUTDIR', 'Generate ruby API from an API description'
     method_options url: :array, file: :array, from_discovery: :boolean, preferred_only: :boolean,
                    verbose: :boolean, names: :string, names_out: :string
-    method_option :preferred_only, default: true
     def gen(dir)
       ensure_active_support
       require 'google/apis/generator'
@@ -55,7 +54,12 @@ module Google
     no_commands do
       def generate_from_url(urls)
         Array(urls).each do |url|
+          begin
             json = discovery.http(:get, url)
+          rescue Google::Apis::ClientError
+            warn sprintf('Failed request, skipping %s', url)
+            next
+          end
           generate_api(json)
         end
       end

script/generate

@@ -8,9 +8,7 @@ URLS=(https://content.googleapis.com/discovery/v1/apis/appsmarket/v2/rest \
       https://content.googleapis.com/discovery/v1/apis/youtubePartner/v1/rest \
       https://content.googleapis.com/discovery/v1/apis/compute/beta/rest \
       https://developers.google.com/my-business/samples/mybusiness_google_rest_v3.json \
-      https://monitoring.googleapis.com/\$discovery/rest?version=v3 \
-      https://www.googleapis.com/discovery/v1/apis/admin/datatransfer_v1/rest \
-      https://www.googleapis.com/discovery/v1/apis/admin/directory_v1/rest
+      https://monitoring.googleapis.com/\$discovery/rest?version=v3
 )
 
-echo 'a' | bundle exec bin/generate-api gen generated --from_discovery=true --names_out=$DIR/api_names_out.yaml --url=${URLS[*]}
+echo 'a' | bundle exec bin/generate-api gen generated --from-discovery --no-preferred-only --names-out=$DIR/api_names_out.yaml --url=${URLS[*]}