swift3 fails to validate grantee in acl

[Christof Schmitt]

This s3-tests case is failing:

======================================================================
FAIL: s3tests.functional.test_s3.test_bucket_acl_grant_nonexist_user
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/s3-tests/virtualenv/lib/python2.6/site-packages/nose/case.py", line 197, in runTest
    self.test(*self.arg)
  File "/s3-tests/s3tests/functional/test_s3.py", line 3758, in test_bucket_acl_grant_nonexist_user
    e = assert_raises(boto.exception.S3ResponseError, bucket.set_acl, policy)
  File "/s3-tests/s3tests/functional/utils.py", line 21, in assert_raises
    raise AssertionError("%s not raised" % excName)
AssertionError: S3ResponseError not raised
-------------------- >> begin captured stdout << ---------------------
<AccessControlPolicy xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Owner><ID>main:mainadmin</ID><DisplayName>main:mainadmin</DisplayName></Owner><AccessControlList><Grant><Grantee xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="CanonicalUser"><ID>main:mainadmin</ID><DisplayName>main:mainadmin</DisplayName></Grantee><Permission>FULL_CONTROL</Permission></Grant><Grant><Grantee xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="CanonicalUser"><ID>_foo</ID><DisplayName>None</DisplayName></Grantee><Permission>FULL_CONTROL</Permission></Grant></AccessControlList></AccessControlPolicy>

--------------------- >> end captured stdout << ----------------------

It looks like the swift3 code does not check whether the grantee id is valid.

[Sivasathurappan Radhakrishnan (siva-radhakrishnan)]

I believe Swift doesn't check if the user is existent or non-existent user in the system. This might be the reason for this error.