Code review comment for lp://qastaging/~caio1982/ubuntu-system-image/remote-sis-generator-skips-metadata

Thanks, Barry! Just filed https://bugs.launchpad.net/ubuntu-system-image/+bug/1461263 for the encoding bit. It might take me a while to write tests for this MR though as I honestly don't know the code much and I see all the other generators are missing tests for metadata (at least for version_detail) and they should have some.