fix rubocop warns in Ruby client's custom spec (#5488)

Author: autopp

samples/openapi3/client/petstore/ruby/spec/custom/pet_spec.rb

@@ -23,7 +23,7 @@
       tag1 = Petstore::Tag.new('id' => 1, 'name' => 'tag1')
       tag2 = Petstore::Tag.new('id' => 2, 'name' => 'tag2')
       category1 = Petstore::Category.new(:id => 1, :name => 'category unknown')
-      # initalize using both string and symbol key
+      # initialize using both string and symbol key
       pet_hash = {
         :id => @pet_id,
         :name => "RUBY UNIT TESTING",
@@ -79,7 +79,7 @@
       rescue Petstore::ApiError => e
         expect(e.code).to eq(404)
         # skip the check as the response contains a timestamp that changes on every reponse
-        #expect(e.message).to eq("Error message: the server returns an error\nHTTP status code: 404\nResponse headers: {\"Date\"=>\"Tue, 26 Feb 2019 04:35:40 GMT\", \"Access-Control-Allow-Origin\"=>\"*\", \"Access-Control-Allow-Methods\"=>\"GET, POST, DELETE, PUT\", \"Access-Control-Allow-Headers\"=>\"Content-Type, api_key, Authorization\", \"Content-Type\"=>\"application/json\", \"Connection\"=>\"close\", \"Server\"=>\"Jetty(9.2.9.v20150224)\"}\nResponse body: {\"code\":1,\"type\":\"error\",\"message\":\"Pet not found\"}")
+        # expect(e.message).to eq("Error message: the server returns an error\nHTTP status code: 404\nResponse headers: {\"Date\"=>\"Tue, 26 Feb 2019 04:35:40 GMT\", \"Access-Control-Allow-Origin\"=>\"*\", \"Access-Control-Allow-Methods\"=>\"GET, POST, DELETE, PUT\", \"Access-Control-Allow-Headers\"=>\"Content-Type, api_key, Authorization\", \"Content-Type\"=>\"application/json\", \"Connection\"=>\"close\", \"Server\"=>\"Jetty(9.2.9.v20150224)\"}\nResponse body: {\"code\":1,\"type\":\"error\",\"message\":\"Pet not found\"}")
         expect(e.response_body).to eq('{"code":1,"type":"error","message":"Pet not found"}')
         expect(e.response_headers).to include('Content-Type')
         expect(e.response_headers['Content-Type']).to eq('application/json')

samples/openapi3/client/petstore/ruby/spec/petstore_helper.rb

@@ -48,5 +48,3 @@ def deserialize_json(s, type)
   response = double('response', headers: headers, body: s)
   API_CLIENT.deserialize(response, type)
 end
-
-