remove unnecessary type check on the module store. XML module stores will throw…

remove unnecessary type check on the module store. XML module stores will throw an exception when deleting an item...

common/lib/xmodule/xmodule/modulestore/store_utilities.py

@@ -137,10 +137,6 @@ def delete_course(modulestore, contentstore, source_location, commit=False):
     courseware store. BE VERY CAREFUL, this is not reversable.
     """
 
-    # first check to see if the modulestore is Mongo backed
-    if not isinstance(modulestore, MongoModuleStore):
-        raise Exception("Expected a MongoModuleStore in the runtime. Aborting....")
-
     # check to see if the source course is actually there
     if not modulestore.has_item(source_location):
         raise Exception("Cannot find a course at {0}. Aborting".format(source_location))