Ping is returning 'scope' in json results, rather than 'namespace'

I believe that changed at some point, and probably the ping was implemented before the change. Now that we are GA, the question is what to do? Deliver both, then eventually we eliminate the duplication (say in some future 3.x?). It is simple enough for the SDKs built on top of LCB to expose it as 'namespace', so perhaps we live with it? Worth pondering in any case.