ACCUMULO-2433 Try to stabilize listscans on ShellServerTest

Remove the ZKI and Connector timing from the 5s that we used to look
for the slow scan that was running. Increase the amount of time inbetween
calls to listscans.
ACCUMULO-2453 Add in commons-httpclient test dependency
Merge branch '1.5.2-SNAPSHOT' into 1.6.0-SNAPSHOT

Conflicts:
	test/src/test/java/org/apache/accumulo/test/ShellServerTest.java
ACCUMULO-2453 Forgot to remove dependency from the default