Fix opaque_keys imports from hotfixes

common/djangoapps/course_modes/tests/factories.py

 from course_modes.models import CourseMode
 from factory.django import DjangoModelFactory
-from xmodule.modulestore.locations import SlashSeparatedCourseKey
+from opaque_keys.edx.locations import SlashSeparatedCourseKey
 
 
 # Factories don't have __init__ methods, and are self documenting

common/djangoapps/course_modes/tests/test_views.py

@@ -7,7 +7,7 @@ from mock import patch, Mock
 
 from course_modes.tests.factories import CourseModeFactory
 from student.tests.factories import CourseEnrollmentFactory, UserFactory
-from xmodule.modulestore.locations import SlashSeparatedCourseKey
+from opaque_keys.edx.locations import SlashSeparatedCourseKey
 
 
 @ddt.ddt

common/djangoapps/student/tests/factories.py

@@ -10,7 +10,7 @@ import factory
 from factory.django import DjangoModelFactory
 from uuid import uuid4
 from pytz import UTC
-from xmodule.modulestore.locations import SlashSeparatedCourseKey
+from opaque_keys.edx.locations import SlashSeparatedCourseKey
 
 # Factories don't have __init__ methods, and are self documenting
 # pylint: disable=W0232, C0111