fix tinymce initialization between edits in eportfolios

fixes a bug where tinymce would not show up after editing/saving rich
text in eportfolios.

test plan:
  - as somebody with an eportfolio, make a page
  - add rich content to the page, and hit save
  - edit the rich content again. you should get the rich content editor
    and save the content. It should update as usual.

fixes CNVS-1366

Change-Id: I29b516c13f9193ef63830ab9082c6866599c649f
Reviewed-on: https://gerrit.instructure.com/20291
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Cam Theriault <cam@instructure.com>
Reviewed-by: Ryan Florence <ryanf@instructure.com>
Product-Review: Ryan Florence <ryanf@instructure.com>

Author: Stanley Stuart

public/javascripts/eportfolio.js

@@ -149,11 +149,11 @@ define([
       $("#edit_page_form,#page_content,#page_sidebar").removeClass('previewing');
       $("#page_content .preview_section").remove();
     }).end().find(".cancel_button").click(function() {
+      $('.edit_section').editorBox('destroy');
       $("#edit_page_form,#page_content,#page_sidebar").removeClass('editing');
       $("#page_content .section.unsaved").remove();
       $(".edit_content_link_holder").show();
       $("#edit_page_form .edit_section").each(function() {
-        $(this).editorBox('destroy');
         $(this).remove();
       });
       $("#page_content .section .form_content").remove();
@@ -179,10 +179,10 @@ define([
         return data;
       },
       beforeSubmit: function(data) {
+        $('.edit_section').editorBox('destroy');
         $("#edit_page_form,#page_content,#page_sidebar").removeClass('editing').removeClass('previewing');
         $("#page_content .section.unsaved,#page_content .section .form_content").remove();
         $("#edit_page_form .edit_section").each(function() {
-          $(this).editorBox('destroy');
           $(this).remove();
         });
         $(this).loadingImage();