Minor work on errors shown within the JS

lms/static/coffee/src/open_ended/open_ended.coffee

@@ -41,7 +41,7 @@ class OpenEnded
   post: (cmd, data, callback) ->
       # if this post request fails, the error callback will catch it
       $.post(@ajax_url + cmd, data, callback)
-        .error => callback({success: false, error: "Error occured while performing this operation"})
+        .error => callback({success: false, error: "Error occured while performing javascript ajax post."})
 
   after_action_wrapper: (target, action_type) ->
     tr_parent = target.parent().parent()

lms/static/coffee/src/staff_grading/staff_grading.coffee

@@ -143,7 +143,7 @@ The standard chunk of Lorem Ipsum used since the 1500s is reproduced below for t
     else
       # TODO: replace with postWithPrefix when that's loaded
       $.post(@ajax_url + cmd, data, callback)
-        .error => callback({success: false, error: "Error occured while performing this operation"})
+        .error => callback({success: false, error: "Error occured while performing javascript AJAX post."})
 
 
 class @StaffGrading