Shorten package name

[dezull]

When packaging a box with a long path, it will fail at tarring:

$ vagrant package --output /home/user/thing/projects/subdir/myvm.box myvm

==> myvm: --- Attempting to package
==> myvm: --- boxname: -VAGRANTSLASH-home-VAGRANTSLASH-user-VAGRANTSLASH-thing-VAGRANTSLASH-projects-VAGRANTSLASH-subdir-VAGRANTSLASH-myvm.box.box
VMware ovftool 4.3.0 (build-10104578)
Opening VI source: vi://[email protected]:443/
Opening VMX target: ZZZZ_tmpdir
Writing VMX file: ZZZZ_tmpdir/-VAGRANTSLASH-home-VAGRANTSLASH-user-VAGRANTSLASH-thing-VAGRANTSLASH-projects-VAGRANTSLASH-subdir-VAGRANTSLASH-myvm.box/-VAGRANTSLASH-home-VAGRANTSLASH-user-VAGRANTSLASH-thing-VAGRANTSLASH-projects-VAGRANTSLASH-subdir-VAGRANTSLASH-myvm.box.vmx
Transfer Completed
Completed successfully
==> myvm: tarring -VAGRANTSLASH-home-VAGRANTSLASH-user-VAGRANTSLASH-thing-VAGRANTSLASH-projects-VAGRANTSLASH-subdir-VAGRANTSLASH-myvm.box.box
tar: AGRANTSLASH-home-VAGRANTSLASH-user-VAGRANTSLASH-thing-VAGRANTSLASH-projects-VAGRANTSLASH-subdir-VAGRANTSLASH-myvm.box.vmx: Volume label is too long (limit is 99 bytes)
Try 'tar --help' or 'tar --usage' for more information.

This PR makes package works similarly to virtualbox provider, eg:

$ vagrant package --output /home/user/thing/projects/subdir/myvm.box myvm
==> kali: Clearing any previously set forwarded ports...
==> kali: Exporting VM...
==> kali: Compressing package to: /home/user/thing/projects/subdir/myvm.box

[josenk]

I don't think that --output option should be a full path??? According to the documentation, it's just a "NAME".

https://www.vagrantup.com/docs/cli/package.html

• --output NAME - The resulting package will be saved as NAME. By default, it will be saved as package.box.

The public boxes: https://app.vagrantup.com/boxes/search that contain a slash "/", all get downloaded as "VAGRANTSLASH".
For example:

• https://app.vagrantup.com/generic/boxes/ubuntu1904
• generic-VAGRANTSLASH-ubuntu1904

So, I use that format for the NAME...

[dezull]

I think that behaviour was changed a while ago? see hashicorp/vagrant@b026be7