Merge pull request #50627 from AliMasarweh/wip-ali-masa-multipart-populate-etag

RGW: Solving the issue of not populating etag in Multipart upload result
Reviewed-by: Daniel Gryniewicz <dang1@ibm.com>

src/rgw/rgw_op.cc

@@ -6611,6 +6611,9 @@ void RGWCompleteMultipart::complete()
       ldpp_dout(this, 0) << "WARNING: failed to unlock " << *serializer.get() << dendl;
     }
   }
+
+  etag = s->object->get_attrs()[RGW_ATTR_ETAG].to_str();
+
   send_response();
 }