[Tachyon-26] test UnderFileSystem.get() code path in Glusterfs Cluster.

Fix the dependency issue in gluster test profile;
Update gluster test instruction in glusterfs setup document.

Signed-off-by: rootfs <hchen@redhat.com>
It is always a local filesystem address, because glusterfs uses a mount point (and thus posix compliant). 
Glusterfs hadoop driver is based on local fs, this snippet could make it more clear
https://github.com/gluster/glusterfs-hadoop/blob/master/src/main/java/org/apache/hadoop/fs/glusterfs/GlusterVolume.java#L44