Revert "ACCUMULO-2316 No more namespacenotfound for table requests"

This reverts commit 98e374b0ea342136d4ef68cd3a266653ea07de11.

Conflicts:
	test/src/test/java/org/apache/accumulo/test/NamespacesIT.java
ACCUMULO-2316 a simpler approach for property security exceptions
Merge branch '1.6.0-SNAPSHOT'

Conflicts:
	core/src/main/java/org/apache/accumulo/core/client/admin/SecurityOperationsImpl.java