bump netplugin-shim
bump netplugin-shim

Submodule src/code.cloudfoundry.org/netplugin-shim 70c6076..e86032d:
  > byte slices for everyone

Signed-off-by: Claudia Beresford <80d58ba8cbfbf831cfa674a754c8439fd7d2f06e@pivotal.io>

cloudfoundry-incubator/guardian-release,cloudfoundry-incubator/guardian-release,cloudfoundry-incubator/guardian-release