[Forms] Use MM-DD in date-time control

Use month and day instead of day-of-year in date-time
control, WTD-1272.

platform/forms/res/templates/controls/datetime.html

@@ -35,8 +35,8 @@
             <span class='field control date'>
                 <input type='text'
                        name='date'
-                       placeholder="YYYY-DDD"
-                       ng-pattern="/\d\d\d\d-\d\d\d/"
+                       placeholder="{{format}}"
+                       ng-pattern="/\d\d\d\d-\d\d-\d\d/"
                        ng-model='datetime.date'
                        ng-required='ngRequired || partiallyComplete'/>
             </span>
@@ -80,4 +80,4 @@
     </ng-form>
 
 
-</div>
+</div>