Automatic merge from submit-queue
Do not cache hyperkube package installation
**What this PR does / why we need it**:
The hyperkube build process could use a cached layer containing out of date packages. For example, the v1.4.0 image contains packages with security vulnerabilities, which should have been available as of the release build date.
This was surfaced from quay.io/clair scanning the hyperkube images:
17bc61b54e
This patch adds a cache-busting comment to the RUN command which installs/updates packages.
ff8f29b724