Imports of package credentials

PathSynopsis
github.com/docker/docker-credential-helpers/client
github.com/docker/docker-credential-helpers/credentials
github.com/docker/docker/cliconfig/configfile
github.com/docker/engine-api/typesPackage types is used for API stability in the types and response to the consumers of the API stats endpoint.
os/execPackage exec runs external commands.
stringsPackage strings implements simple functions to manipulate UTF-8 encoded strings.