This dependency is problematic because of the many replaces it brings
with it. This makes it hard to import external-snapshotter in 3rd
party projects without having a lot of `replace` directives in those
projects as well.
The only usage of that import was to get two very simple utility
functions so I copied them over to this repo.
This commit also adds the compatibility with dep (Go dependency
management tool) via symlink creation (same method applied in
kubernetes-csi/csi-test)
TODO: fix hack/update-generated-code.sh
Fixes issue #239.
Signed-off-by: Alex Szakaly <alex.szakaly@gmail.com>