A missing synced folders cache indicates an empty cache, not a failure
that should be handled by the caller. The cache file is missing from
data dirs created by an earlier version of Vagrant.
Fixes#3550.
In addition to checking if a port is open, we now check if a port is
"leased", which we do for a period of 60 seconds. This gives the provider
time to actually put the port into use.
Initial work
commands/up: make sure all names to with_target_vms are strings
providers/docker: create a docker host VM if needed
providers/docker: executor abstraction for driver to eventually support remote
providers/docker: vagrant executor
providers/docker: support creating the machine
providers/docker: status works if host VM is gone
providers/docker: use start fence to get real docker output
core: Call preserves stack ordering
core: support Message post option
providers/docker: Guard some features with HasSSH checks
providers/docker: much better messaging around create/destroy
providers/docker: output the container ID on create
providers/docker: copy the hostmachine Vagrantfile to the data dir
providers/docker: should make host machine before any up action
providers/docker: HandleBox before the host machine
providers/virtualbox: functional_vboxsf to disable vboxsf
providers/virtualbox: synced folder usable method should take 2 args
providers/docker: default machine name to :default
before this patch:
```
$ vagrant box remove --box-version 0.2.9 berendt/ubuntu-14.04-amd64
You requested to remove the box 'berendt/ubuntu-14.04-amd64' version '0.2.9' with
provider 'virtualbox', but that specific version of the box is
not install. Please double-check and try again. The available versions
for this box are:
0.2.11, 0.2.10
```
after this patch:
```
You requested to remove the box 'berendt/ubuntu-14.04-amd64' version '0.2.9' with
provider 'virtualbox', but that specific version of the box is
not install. Please double-check and try again. The available versions
for this box are:
* 0.2.10
* 0.2.11
```
