When we delete the shared instance, in addition to erasing the data
in the share, we should disconnect the client's mount point to
prevent the data from being written in.
Closes-Bug: #1886010
Change-Id: I7a334fb895669cc807a288e6aefe62154a89a7e4
(cherry picked from commit 9d44ba0b6a)
(cherry picked from commit 4f2e400a6b)
(cherry picked from commit d9e6743ba5)
(cherry picked from commit 4e75f14c76)
(cherry picked from commit 0ac95862be)