revert to 1617395

git-svn-id: https://svn.apache.org/repos/asf/hama/trunk@1618812 13f79535-47bb-0310-9956-ffa450edef68
HAMA-914: Boolean flag (isCompressed) is required only when runtime compression is enabled.

git-svn-id: https://svn.apache.org/repos/asf/hama/trunk@1619042 13f79535-47bb-0310-9956-ffa450edef68
Merge latest trunk revision 6c2bc4f HAMA-914