FindImage with blob=False crashes server

FindImage with blob=False crashes server

Server error:
```
"vdms: src/ImageCommand.cc:238: virtual Json::Value VDMS::FindImage::construct_responses(Json::Value&, const Json::Value&, VDMS::protobufs::queryMessage&, const string&): Assertion `findImage.isMember(""entities"")' failed.
/start.sh: line 5:    13 Aborted                 (core dumped) ./vdms
```