vendor: clean up
# go-runc client for runc; master as of 12/16/2016
github.com/crosbymichael/go-runc 2fdd3cd06f7443a55f6eb14ead2cac507506e718
-# distribution code from Docker; latest tagged release as of 12/16/2016
-github.com/docker/distribution v2.6.0-rc.1
# go-metrics client to prometheus; master as of 12/16/2016
github.com/docker/go-metrics 0f35294225552d968a13f9c5bc71a3fa44b2eb87
# prometheus client; latest release as of 12/16/2016
