ACCUMULO-3148 Change the verification of HalfDeadTServerIT

The test can fail in situations where we expect it to pass
(tserver dies and had lost its ZK session, but "Session expired"
doesn't make it into the stdout). Try to make the verification
a bit more reliable.
ACCUMULO-3140 made user initiated majC wait for current minC to finish
Merge branch '1.5.3-SNAPSHOT' into 1.6.1-SNAPSHOT

Conflicts:
	server/tserver/src/main/java/org/apache/accumulo/tserver/Tablet.java
Merge branch '1.6.1-SNAPSHOT'
Merge branch '1.6.1-SNAPSHOT' of https://git-wip-us.apache.org/repos/asf/accumulo into 1.6.1-SNAPSHOT
Merge branch '1.6.1-SNAPSHOT'

Conflicts:
	server/tserver/src/main/java/org/apache/accumulo/tserver/tablet/Tablet.java
ACCUMULO-3155 Fix example config to make the batchwalkers run every 30 minutes instead of 3000 minutes
Merge branch '1.5.3-SNAPSHOT' into 1.6.1-SNAPSHOT
Merge branch '1.6.1-SNAPSHOT'