Upgrade boot2docker to v0.9.1
Upgrade boot2docker to version 0.9.1
I use a custom ISO to support NFS.
It has not been used, because the official ISO doesn't support NFS.
Merge branch 'hnakamur-boot2docker-0.9.1' into classic
Disable the provider's native synced folder

because boot2docker has no native drivers
Disable synced folder by default