Install ginkgo on demand via `go get -u` rather than keeping a copy it's
entire source code in the vendor dirctory. The main motivation for that
is to make `golangci-lint` happy which is continuously throwing up on
the import of a program (i.e., ginkgo). The linter is broken and stupid
as it ignores flags to ignore dirs and ignores build tags (at least some
linters do) which is blocking us from updating to newer versions.
Signed-off-by: Valentin Rothberg <rothberg@redhat.com>
