Support custom docker args for weave-plugin
Support custom docker args for weave-plugin

WEAVEPLUGIN_DOCKER_ARGS environment variable is used to pass custom args when creating plugin container
n054/weave,weaveworks/weave,paulbellamy/weave,n054/weave,paulbellamy/weave,paulbellamy/weave,n054/weave,weaveworks/weave,weaveworks/weave,weaveworks/weave,n054/weave,n054/weave,paulbellamy/weave