pom.xml: make hadoop version configurable
pom.xml: make hadoop version configurable

By default, hfind bundles Hadoop version 0.20.2.
One can override it via the hadoop.version parameter.

This fixes #1.

Testing Done: built the following artifacts

  mvn clean install
  mvn -Dhadoop.version=0.20.2-cdh3u1 clean install
  mvn -Dhadoop.version=0.20.2-cdh3u2 clean install
  mvn -Dhadoop.version=0.20.2-cdh3u3 clean install
  mvn -Dhadoop.version=1.0.0 clean install
  mvn -Dhadoop.version=1.0.1 clean install
  mvn -Dhadoop.version=1.0.2 clean install

Signed-off-by: Pierre-Alexandre Meyer <ff019a5748a52b5641624af88a54a2f0e46a9fb5@mouraf.org>

pierre/hfind,pierre/hfind