Description of problem:
Brick is not detached successfully while brick_mux is enabled.

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


How reproducible:
Always

Steps to Reproduce:
1. Setup 3 node cluster environment
2. Enable brick_mux
3. Run below loop to setup 50 volumes
   for i in {1..50}; do gluster v create testvol$i replica 3 <node1>:/home/testvol/b$i <node2>:/home/testvol/b$i <node3>:/home/testvol/b$i force; gluster v start testvol$i;done
4. Run below loop to stop volume
   for i in {2..50}; do gluster v stop testvol$i --mode=script; sleep 1; ;done
5. After run above loop check brick in running process
   ls -lrth /proc/`pgrep glusterfsd`/fd | grep b | grep -v .glusterfs
   the command is showing multiple bricks are still part of the running process.
Actual results:
   Bricks are not detached successfully.

Expected results:
   Bricks should be detached successfully.

Additional info: