ACCUMULO-2184 Fix "Unknown" HDFS usage entry in "Accumulo Master" table on overview monitor page
Merge branch '1.4.5-SNAPSHOT' into 1.5.1-SNAPSHOT

Conflicts:
	server/src/main/java/org/apache/accumulo/server/monitor/servlets/DefaultServlet.java
Merge branch '1.5.1-SNAPSHOT' into 1.6.0-SNAPSHOT