CreateBucket and PutBucketAcl with x-amz-grant-* headers stored the
requested grants plus a FULL_CONTROL grant for the bucket owner, so
GetBucketAcl returned a grant AWS doesn't. On AWS the headers replace the
whole ACL and the owner gets FULL_CONTROL only when a header names it.
UpdateACL now keeps just the header grants when there are any. A canned
ACL and a bucket created without grants still get the owner's FULL_CONTROL
grant. The owner keeps full access either way, since aclAllows lets the
bucket owner perform any action regardless of grants.
Fixes#1407
dualfroz
upstream