[Bug 1037634] The devicemapper volumes are not removed after container is removed

[Red Hat Bugzilla]

https://bugzilla.redhat.com/show_bug.cgi?id=1037634

--- Comment #3 from Michal Fojtik  ---
Also there might be additional bug, related to this. I just discovered that my
/var/lib/docker folder use 11G of space, with no containers running and no
extra images... Seems like they will need to be collected as well :-)

in /var/lib/docker:

11G     ./devicemapper
....
3.2G    ./devicemapper/mnt
11G     ./devicemapper