Add locking around dpkg installs [#150116864](https://www.pivotaltracker.com/story/show/150116864)
Add locking around dpkg installs
[#150116864](https://www.pivotaltracker.com/story/show/150116864)

cloudfoundry-incubator/nfs-volume-release,cloudfoundry-incubator/nfs-volume-release,cloudfoundry-incubator/nfs-volume-release