The iterator function getmntent() is not stable. It may skip
entries if the contents of the iterated file changes, which
is the case with /proc/mounts when filesystems are unmounted.
As a result, some filesystems were never unmounted.
To fix this, iteratation is now restarted after every
sucessful unmount.
Signed-off-by: Robert Andersson <robert.m.andersson@atlascopco.com>
Signed-off-by: Ming Liu <liu.ming50@gmail.com>
