QA::Page::Component::Dropzone#initialize needs a QA::Page::Base object

Signed-off-by: Rémy Coutable <remy@rymai.me>

qa/qa/page/component/dropzone.rb

@@ -4,6 +4,8 @@ module QA
       class Dropzone
         attr_reader :page, :container
 
+        # page      - A QA::Page::Base object
+        # container - CSS selector of the comment textarea's container
         def initialize(page, container)
           @page = page
           @container = container

qa/qa/page/project/issue/show.rb

@@ -27,7 +27,7 @@ module QA
             fill_in(with: text, name: 'note[note]')
 
             unless attachment.nil?
-              QA::Page::Component::Dropzone.new(page, '.new-note')
+              QA::Page::Component::Dropzone.new(self, '.new-note')
                 .attach_file(attachment)
             end