Relax bucket creation schema

Apparently some AWS-supplied tools use undocumented root elements.

Change-Id: I3d56f9560c2d96b08e6837d053fdff654c531062
Closes-Bug: #1611749

doc/rnc/create_bucket_configuration.rnc

@@ -1,4 +1,4 @@
 start =
-  element CreateBucketConfiguration {
+  element * {
     element LocationConstraint { xsd:string }
   }

swift3/schema/create_bucket_configuration.rng

@@ -1,7 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <grammar xmlns="http://relaxng.org/ns/structure/1.0" datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes">
   <start>
-    <element name="CreateBucketConfiguration">
+    <element>
+      <anyName/>
       <element name="LocationConstraint">
         <data type="string"/>
       </element>

swift3/test/unit/test_bucket.py

@@ -363,9 +363,8 @@ class TestSwift3Bucket(Swift3TestCase):
         self.assertEqual(status.split()[0], '200')
         self.assertEqual(headers['Location'], '/bucket')
 
-    @s3acl
-    def test_bucket_PUT_with_location(self):
-        elem = Element('CreateBucketConfiguration')
+    def _test_bucket_PUT_with_location(self, root_element):
+        elem = Element(root_element)
         SubElement(elem, 'LocationConstraint').text = 'US'
         xml = tostring(elem)
 
@@ -377,6 +376,20 @@ class TestSwift3Bucket(Swift3TestCase):
         status, headers, body = self.call_swift3(req)
         self.assertEqual(status.split()[0], '200')
 
+    @s3acl
+    def test_bucket_PUT_with_location(self):
+        self._test_bucket_PUT_with_location('CreateBucketConfiguration')
+
+    @s3acl
+    def test_bucket_PUT_with_ami_location(self):
+        # ec2-ami-tools apparently uses CreateBucketConstraint instead?
+        self._test_bucket_PUT_with_location('CreateBucketConstraint')
+
+    @s3acl
+    def test_bucket_PUT_with_strange_location(self):
+        # Even crazier: it doesn't seem to matter
+        self._test_bucket_PUT_with_location('foo')
+
     def test_bucket_PUT_with_canned_acl(self):
         req = Request.blank('/bucket',
                             environ={'REQUEST_METHOD': 'PUT'},