ACCUMULO-1637 Rework the hadoop append/sync checks trying to match what
Hadoop is doing internally by default.
ACCUMULO-1637 Lifting the ticket message into its own string constant
ACCUMULO-1782 Point bulk load tests away from HDFS root

This is a follow-on patch to ACCUMULO-1563, which adjusted directories
in some tests to avoid writing into the root of HDFS.

Signed-off-by: Eric Newton <eric.newton@gmail.com>