hadoop: start deprecation of old client

The old hadoop client is not being compiled nor tested and has been replaced by the code in src/java.
This patch removes the entries in configure.ac and Makefile.am as well as all
of the source under src/client/hadoop.

Signed-off-by: Noah Watkins <noahwatkins@gmail.com>
Reviewed-by: Joe Buck <jbbuck@gmail.com>