[SHELL] Purge close_region command that allows by-pass of Master

In AMv2, if a RS is not aligned with Master notions of how the world is, then the Master will kill the deviant RS (TODO: is forcing compliance via less radical means – but that is how it is currently).

The shell currently allows by-passing the Master to make cluster modifications such as our being able to send a close directly to a RegionServer for it to execute locally. This facility was used in the past to do fix-up when Master lost account of Region locations. In the new regime, such mis-accounting should no longer happen and, should a user mistakenly do an explicit close against a RS, the consequences will be more than the user bargained for; the Master will shut down the RS as soon as it reports close of a Region the master thinks should be open (No independence allowed!).

This issue is to review shell Region and Table manipulation commands to purge those that by-pass Master or at least to add big warning.