HAMA-867: change url to maven central repository

git-svn-id: https://svn.apache.org/repos/asf/hama/trunk@1571556 13f79535-47bb-0310-9956-ffa450edef68
maven seems update required dependencies automatically.

git-svn-id: https://svn.apache.org/repos/asf/hama/trunk@1571564 13f79535-47bb-0310-9956-ffa450edef68
Merge branch 'trunk' of https://github.com/apache/hama into trunk