ACCUMULO-3401 Clean up old AbstractMacIT classes

  Remove usage of deprecated SimpleMacIT and consolidate AbstractMacIT with
  ConfigurableMacIT. Update javadocs to clarify usage.
Merge branch '1.6'

Conflicts:
	test/src/test/java/org/apache/accumulo/test/functional/AbstractMacIT.java
	test/src/test/java/org/apache/accumulo/test/functional/ConfigurableMacIT.java
	test/src/test/java/org/apache/accumulo/test/functional/SimpleMacIT.java
Merge remote-tracking branch 'origin/master'