ACCUMULO-1891 sets errorcode to default if it is null during message lookup.

Signed-off-by: Christopher Tubbs <ctubbsii@apache.org>
Merge branch '1.4.5-SNAPSHOT' into 1.5.1-SNAPSHOT

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