test: remove only_xmodules

This function was only used by tests. It was breaking tests from the `xmodule`
package on the devstack because the dist.key of its entry_points is `open-edx`.

xmodule/modulestore/__init__.py

@@ -1386,10 +1386,3 @@ class ModuleStoreWriteBase(ModuleStoreReadBase, ModuleStoreWrite):
         """
         if self.signal_handler:
             self.signal_handler.send("item_deleted", usage_key=usage_key, user_id=user_id)
-
-
-def only_xmodules(identifier, entry_points):
-    """Only use entry_points that are supplied by the xmodule package"""
-    from_xmodule = [entry_point for entry_point in entry_points if entry_point.dist.key == 'xmodule']
-
-    return default_select(identifier, from_xmodule)

xmodule/tests/test_import.py

@@ -17,7 +17,6 @@ from xblock.fields import Integer, Scope, String
 from xblock.runtime import DictKeyValueStore, KvsFieldData
 
 from xmodule.fields import Date
-from xmodule.modulestore import only_xmodules
 from xmodule.modulestore.inheritance import InheritanceMixin, compute_inherited_metadata
 from xmodule.modulestore.xml import ImportSystem, LibraryXMLModuleStore, XMLModuleStore
 from xmodule.tests import DATA_DIR
@@ -69,7 +68,6 @@ class BaseCourseTestCase(TestCase):
             DATA_DIR,
             source_dirs=[name],
             xblock_mixins=(InheritanceMixin,),
-            xblock_select=only_xmodules,
         )
         courses = modulestore.get_courses()
         assert len(courses) == 1

xmodule/tests/xml/factories.py

@@ -11,7 +11,6 @@ from fs.osfs import OSFS
 from lxml import etree
 from xblock.mixins import HierarchyMixin
 
-from xmodule.modulestore import only_xmodules
 from xmodule.modulestore.inheritance import InheritanceMixin
 from xmodule.x_module import XModuleMixin
 
@@ -72,7 +71,6 @@ class XmlImportFactory(Factory):
 
     filesystem = OSFS(mkdtemp())
     xblock_mixins = (InheritanceMixin, XModuleMixin, HierarchyMixin)
-    xblock_select = only_xmodules
     url_name = Sequence(str)
     attribs = {}
     policy = {}