[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 a little bit confused. If it is always a local file system uri, when we have the following code path happened. It never goes to underfshdfs, since its scheme always refers to local file system, right?
```
    String glusterfsPrefix = "glusterfs:///";
    if (fsDefaultName.startsWith(glusterfsPrefix)) {
      tConf.set("fs.glusterfs.impl", CommonConf.get().UNDERFS_GLUSTERFS_IMPL);
      tConf.set("mapred.system.dir", CommonConf.get().UNDERFS_GLUSTERFS_MR_DIR);
      tConf.set("fs.glusterfs.volumes", CommonConf.get().UNDERFS_GLUSTERFS_VOLUMES);
      tConf.set("fs.glusterfs.volume.fuse." + CommonConf.get().UNDERFS_GLUSTERFS_VOLUMES,
          CommonConf.get().UNDERFS_GLUSTERFS_MOUNTS);
    } else {
      tConf.set("fs.hdfs.impl", CommonConf.get().UNDERFS_HDFS_IMPL);

      // To disable the instance cache for hdfs client, otherwise it causes the
      // FileSystem closed exception. Being configurable for unit/integration
      // test only, and not expose to the end-user currently.
      tConf.set("fs.hdfs.impl.disable.cache",
          System.getProperty("fs.hdfs.impl.disable.cache", "false"));
    }
```