rgw/sse-s3: fix bucket encryption of multipart upload

Multipart upload missing encryption when we have bucket encryption
policy. Fix it by fetching bucket encryption policy and resolving
defaults at multipart init op.

Fixes: 464fda8.

Signed-off-by: Tongliang Deng <dengtongliang@gmail.com>

src/rgw/rgw_op.cc

@@ -6225,8 +6225,10 @@ void RGWInitMultipart::execute(optional_yield y)
   bufferlist aclbl, tracebl;
   rgw::sal::Attrs attrs;
 
-  if (get_params(y) < 0)
+  op_ret = get_params(y);
+  if (op_ret < 0) {
     return;
+  }
 
   if (rgw::sal::Object::empty(s->object.get()))
     return;

src/rgw/rgw_rest_s3.cc

@@ -3876,10 +3876,19 @@ void RGWSetRequestPayment_ObjStore_S3::send_response()
 
 int RGWInitMultipart_ObjStore_S3::get_params(optional_yield y)
 {
+  int ret;
+
+  map_qs_metadata(s, true);
+  ret = get_encryption_defaults(s);
+  if (ret < 0) {
+    ldpp_dout(this, 5) << __func__ << "(): get_encryption_defaults() returned ret=" << ret << dendl;
+    return ret;
+  }
+
   RGWAccessControlPolicy_S3 s3policy(s->cct);
-  op_ret = create_s3_policy(s, driver, s3policy, s->owner);
-  if (op_ret < 0)
-    return op_ret;
+  ret = create_s3_policy(s, driver, s3policy, s->owner);
+  if (ret < 0)
+    return ret;
 
   policy = s3policy;