Automatic merge from submit-queue (batch tested with PRs 43558, 48261, 42376, 46803, 47058)

kubelet: remove unused bandwidth shaping teardown code

Since v1.5 and the removal of --configure-cbr0:

0800df74 "Remove the legacy networking mode --configure-cbr0"

kubelet hasn't done any shaping operations internally.  They
have all been delegated to network plugins like kubenet or
external CNI plugins.  But some shaping code was still left
in kubelet, so remove it now that it's unused.

@freehan @thockin @bprashanth