Revert "Merge branch 'master' of github.com:gluster/hadoop-glusterfs"

This reverts commit 8c796b823e4443434dffbb31cf3c2a21cd5503e0, reversing
changes made to 2e1528e623399fb9ab0b2a42fd540805241a8e69.
Revert "MappedByteBuffer implementation"

This reverts commit 2e1528e623399fb9ab0b2a42fd540805241a8e69.