grab all AB Standards not just grade types

closes PS-488

test plan:
  1. run academic benchmark import with state guid
  2. once that is imported verify all standards are imported

Change-Id: I82455878ea947e33a0c8b5974582106b0633c86e
Reviewed-on: https://gerrit.instructure.com/22183
Reviewed-by: Simon Williams <simon@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: Jake Sorce <jake@instructure.com>
QA-Review: Jake Sorce <jake@instructure.com>

vendor/plugins/academic_benchmark/lib/academic_benchmark/standard.rb

@@ -6,8 +6,6 @@ class Standard
     @parent = parent
     @children = []
 
-    return if type == 'course'
-
     if has_items?
       items.each do |itm|
         Standard.new(itm, self)