Remove DOCKER_DRIVER: overlay2 from CI
Removes DOCKER_DRIVER: overlay2
, which has been the default value since Docker 17.09 CE.
Part of &7935
Signed-off-by: Takuya Noguchi takninnovationresearch@gmail.com
Removes DOCKER_DRIVER: overlay2
, which has been the default value since Docker 17.09 CE.
Part of &7935
Signed-off-by: Takuya Noguchi takninnovationresearch@gmail.com