Simplified module_has_submodule on Python >= 3.3.

Stopped using the imp module on Python >= 3.3. Refs #21628.

django/utils/module_loading.py

@@ -1,7 +1,6 @@
 from __future__ import absolute_import  # Avoid importing `importlib` from this package.
 
 import copy
-import imp
 from importlib import import_module
 import os
 import sys
@@ -87,7 +86,28 @@ def autodiscover_modules(*args, **kwargs):
                 raise
 
 
-def module_has_submodule(package, module_name):
+if sys.version_info[:2] >= (3, 3):
+    if sys.version_info[:2] >= (3, 4):
+        from importlib.util import find_spec as importlib_find
+    else:
+        from importlib import find_loader as importlib_find
+
+    def module_has_submodule(package, module_name):
+        """See if 'module' is in 'package'."""
+        try:
+            package_name = package.__name__
+            package_path = package.__path__
+        except AttributeError:
+            # package isn't a package.
+            return False
+
+        full_module_name = package_name + '.' + module_name
+        return importlib_find(full_module_name, package_path) is not None
+
+else:
+    import imp
+
+    def module_has_submodule(package, module_name):
         """See if 'module' is in 'package'."""
         name = ".".join([package.__name__, module_name])
         try: