Some test changes; maybe good?
Make XML construction a bit more readable.
Fix swift3 behavior with set_acl to existing container

S3 allows a bucket PUT with an X-Aws-Acl header (e.g. canned acl) and an
"acl" query param.  But swift3 was erroneously returning
BucketAlreadyExists.  This patch fixes swift3 to allow this action which
S3 allows.
Pull some test output to STDERR back out.
Merge branch 'upstream_master'

Conflicts:
	swift3/test/unit/test_swift3.py