This bug was initially created as a copy of Bug #1721357

Description of problem:

The new pass-thru feature which is enabled by default in master causes internal dht xattrs to be visible on the mount point.


Version-Release number of selected component (if applicable):


How reproducible:

Consistently 
Steps to Reproduce:
1. Install release 3.12 and create a 1x3 volume 
2. Fuse mount the volume and create some directories (dir-1 to dir-10)  and files on the volume
3. Upgrade the node to the latest master and fuse mount the volume
4. Run getfattr -e hex -m . -d /mnt/fuse/dir*



Actual results:
# file: dir-10
security.selinux=0x73797374656d5f753a6f626a6563745f723a6675736566735f743a733000
trusted.glusterfs.dht.mds=0x00000000
user.dirtest=0x64697274657374

# file: dir-2
security.selinux=0x73797374656d5f753a6f626a6563745f723a6675736566735f743a733000
trusted.glusterfs.dht.mds=0x00000000
user.dirtest=0x64697274657374

# file: dir-3
security.selinux=0x73797374656d5f753a6f626a6563745f723a6675736566735f743a733000
trusted.glusterfs.dht.mds=0x00000000
user.dirtest=0x64697274657374

...


Expected results:

trusted.glusterfs.dht.mds is an internal xattr and should not be visible on the mount point.

Additional info:

This was introduced by the pass-through feature.