Export functions from __init__

As a library it would be useful to call functions from oslo_cache rather
than having to import core.

Change-Id: Ia2f785ec745d9777c230f51333cb0d285bf1ba53

oslo_cache/__init__.py

@@ -0,0 +1,23 @@
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+
+from oslo_cache.core import *  # noqa
+
+
+__all__ = [
+    'configure',
+    'configure_cache_region',
+    'create_region',
+    'get_memoization_decorator',
+    'NO_VALUE',
+]