rgw: cleanup for RGWDeleteObj::verify_permission()

- if the 'Effect' field of user policy and bucket policy
  is set to 'Allow', RGWDeleteObj::verify_permission()
  should return 0 instead of true;

- as the same with bucket policy, if the 'Effect' field
  of user policy is set to 'Deny', RGWDeleteObj::verify_permission()
  should return -EACCES instead of false;

Signed-off-by: Enming.Zhang <zvampirem77@gmail.com>
(cherry picked from commit 8633464)

Conflicts:
	src/rgw/rgw_op.cc : Resolved in verify_permission

src/rgw/rgw_op.cc

@@ -4238,7 +4238,7 @@ int RGWDeleteObj::verify_permission()
 				 rgw::IAM::s3DeleteObjectVersion,
 				 ARN(s->bucket, s->object.name));
     if (r == Effect::Allow)
-      return true;
+      return 0;
     else if (r == Effect::Deny)
       return -EACCES;
   }