Add license header to exceptions.py

Previously openstack_auth/exceptions.py had no license header.

Change-Id: Idf3347a54a0ce28cc7efc297e43ad4516ef96cfe

openstack_auth/exceptions.py

@@ -1,3 +1,17 @@
+# 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.
+
+
 class KeystoneAuthException(Exception):
     """ Generic error class to identify and catch our own errors. """
     pass