Fix Rubocop offenses

lib/apipie/errors.rb

@@ -62,7 +62,7 @@ class ParamInvalid < DefinedParamError
     attr_accessor :value, :error
 
     def initialize(param, value, error)
-      super param
+      super(param)
       @value = value
       @error = error
     end

lib/apipie/generator/swagger/config.rb

@@ -24,7 +24,7 @@ class Config
               HEREDOC
             )
 
-            send("#{attribute}=", value)
+            send(:"#{attribute}=", value)
           end
 
           old_setter_method = "swagger_#{attribute}"

lib/tasks/apipie.rake

@@ -186,11 +186,11 @@ namespace :apipie do
     av = renderer
     File.open(file_name, "w") do |f|
       variables.each do |var, val|
-        av.instance_variable_set("@#{var}", val)
+        av.instance_variable_set(:"@#{var}", val)
       end
       f.write av.render(
         :template => "#{template}",
-        :layout => (layout && "apipie/#{layout}"))
+        :layout => layout && "apipie/#{layout}")
     end
   end
 

spec/lib/swagger/rake_swagger_spec.rb

@@ -151,7 +151,7 @@ def expect_response_params_def(http_method, path, response_code, param_name, fie
 
     describe 'apipie:did_swagger_change[development,form_data,_tmp]' do
       it "keeps a reference file" do
-        expect(Pathname(ref_output).children.count).to eq(2)  # one file for each language
+        expect(Pathname(ref_output).children.count).to eq(2) # one file for each language
       end
     end
   end