add form control labels to date fields on quizzes edit page

fixes CNVS-6533

test plan
- make sure that the labels for the dates on quizzes edit control their
  respective form fields

Change-Id: I62631368d07652c866f54844a44aab736d45b1e4
Reviewed-on: https://gerrit.instructure.com/22962
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Myller de Araujo <myller@instructure.com>
Reviewed-by: Stanley Stuart <stanley@instructure.com>
Product-Review: Derek DeVries <ddevries@instructure.com>

Author: Derek DeVries

app/views/jst/assignments/DueDateOverride.handlebars

@@ -2,24 +2,24 @@
 
 <div class="due-date-override-headers clearfix">
   <div class="section-header">
-    {{#t "overrides.for"}}
-      For
-    {{/t}}
+    <label for="overrides_course_section">
+    {{#t "overrides.for"}}For{{/t}}
+    </label>
   </div>
   <div class="due-date-header">
-    {{#t "overrides.due_date"}}
-      Due Date
-    {{/t}}
+    <label for="overrides_due_date">
+    {{#t "overrides.due_date"}}Due Date{{/t}}
+    </label>
   </div>
   <div class="lock-header">
-    {{#t "overrides.available_from"}}
-      Available From
-    {{/t}}
+    <label for="overrides_unlock_at">
+    {{#t "overrides.available_from"}}Available From{{/t}}
+    </label>
   </div>
   <div class="unlock-header">
-    {{#t "until"}}
-      Until
-    {{/t}}
+    <label for="overrides_lock_at">
+    {{#t "until"}}Until{{/t}}
+    </label>
   </div>
 
 </div>

app/views/jst/assignments/DueDateView.handlebars

@@ -1,21 +1,21 @@
 <form>
   {{#with assignment_override}}
-  <select class="section-list input-small" name="course_section_id">
+  <select class="section-list input-small" name="course_section_id" id="overrides_course_section">
   </select>
 
   <div class="date_field_container">
     <input value="{{datetimeFormatted due_at}}" name="due_at" type="text"
-    class="input-small date_field">
+    class="input-small date_field" id="overrides_due_date">
   </div>
 
   <div class="date_field_container">
     <input name="unlock_at" value="{{datetimeFormatted unlock_at}}" type="text"
-    class="date_field">
+    class="date_field" id="overrides_unlock_at">
   </div>
 
   <div class="date_field_container to">
     <input name="lock_at" value="{{datetimeFormatted lock_at}}" type="text"
-    class="date_field">
+    class="date_field" id="overrides_lock_at">
   </div>
 
   <div>