Remove v0.10 check

This fixes https://github.com/pkrumins/node-lazy/issues/32#issuecomment-20165665 for me and all the tests continue to pass under v0.10.x and v0.8.x

So either the behaviour was not needed - or it wasn't being covered by the tests. If it's the latter then this pull request may break when used with other streams, but I have no idea which ones.