fb917bf10b
Problem: In changelog xlator after destroying listener it call's
unlink to delete changelog socket file but socket file
reference is not cleaned up from process memory
Solution: 1) To cleanup reference completely from process memory
serialize transport cleanup for changelog and then
unlink socket file
2) Brick xlator will notify GF_EVENT_PARENT_DOWN to next
xlator only after cleanup all xprts
Test: To test the same run below steps
1) Setup some volume and enable brick mux
2) kill anyone brick with gf_attach
3) check changelog socket for specific to killed brick
in lsof, it should cleanup completely
fixes: bz#1600145
Change-Id: Iba06cbf77d8a87b34a60fce50f6d8c0d427fa491
Signed-off-by: Mohit Agrawal <moagrawal@redhat.com>