Improve bad tserver handling code

The Accumulo master has some code that kills bad servers. This code caused #1456. While reviewing a fix to lessen the possible bite of this code, the question was raised what positive value does the code have? Need to research this in order to make an informed decision about the future direction of this code.

Start by reviewing the Accumulo master’s code that kills bad servers and the failure described in issue #1456. Determine what positive value this handling provides and document an evidence-based direction for its future; the issue is done when that decision is clear.

Written by the indexing model from the issue text.