Restore Glusterfs with update 

Migrate glusterfs-hadoop to maven central from s3; update versions; add configuration setting documentation.
There are three new configurable parameters in the template above, but only two are explained here:

+  -Dtachyon.underfs.glusterfs.volumes=$TACHYON_UNDERFS_GLUSTER_VOLUMES
 +  -Dtachyon.underfs.glusterfs.mounts=$TACHYON_UNDERFS_GLUSTER_MOUNTS
 +  -Dtachyon.underfs.glusterfs.mapred.system.dir=$TACHYON_UNDERFS_GLUSTER_MR_DIR