title: Vagrant up causes guest additions to reinstall each time, why?
body: <p>Ive had to move onto a new laptop running windows 10, so I have installed the latest Virtual box (6) and vagrant (2.2.6). I pulled down my project and ran a vagrant up to build the box and deploy all my work, but there was an issue with guest additions. The box is Centos 7, so after first launch, I carried out a yum update on the box and added vagrant plugins vbguest and hostsupdater to my local vagrant install. I also had to install deltarpms to get the update to work.</p>
  
  <p>However each time I now up or reload the box, it says there is an issue with vbguest tools missing. IT then proceeeds to uninstall the VGA, reinstall the same version and then tell me it hasnt installed properly. However shared folders do appear to work.  Any ideas what I can do to fix this on upload, full output below.</p>
  
  <pre><code>PS C:\Users\Paul M\projects\centos-docker&gt; vagrant reload
  ==&gt; default: [vagrant-hostsupdater] Removing hosts
  ==&gt; default: Attempting graceful shutdown of VM...
  ==&gt; default: Checking if box 'bento/centos-7.4' version '201709.15.0' is up to date...
  ==&gt; default: Clearing any previously set forwarded ports...
  ==&gt; default: Clearing any previously set network interfaces...
  ==&gt; default: Preparing network interfaces based on configuration...
      default: Adapter 1: nat
  ==&gt; default: Forwarding ports...
      default: 8898 (guest) =&gt; 8898 (host) (adapter 1)
      default: 8899 (guest) =&gt; 8899 (host) (adapter 1)
      default: 22 (guest) =&gt; 2222 (host) (adapter 1)
  ==&gt; default: Booting VM...
  ==&gt; default: Waiting for machine to boot. This may take a few minutes...
      default: SSH address: 127.0.0.1:2222
      default: SSH username: vagrant
      default: SSH auth method: private key
  ==&gt; default: Machine booted and ready!
  [default] A Virtualbox Guest Additions installation was found but no tools to rebuild or start them.
  Loaded plugins: fastestmirror
  Loading mirror speeds from cached hostfile
   * base: mirror.vorboss.net
   * extras: www.mirrorservice.org
   * updates: www.mirrorservice.org
  Package kernel-devel-3.10.0-1062.7.1.el7.x86_64 already installed and latest version
  Package kernel-devel-3.10.0-1062.7.1.el7.x86_64 already installed and latest version
  Package gcc-4.8.5-39.el7.x86_64 already installed and latest version
  Package binutils-2.27-41.base.el7_7.1.x86_64 already installed and latest version
  Package 1:make-3.82-24.el7.x86_64 already installed and latest version
  Package 4:perl-5.16.3-294.el7_6.x86_64 already installed and latest version
  Package bzip2-1.0.6-13.el7.x86_64 already installed and latest version
  Package elfutils-libelf-devel-0.176-2.el7.x86_64 already installed and latest version
  Nothing to do
  Copy iso file C:\Program Files\Oracle\VirtualBox/VBoxGuestAdditions.iso into the box /tmp/VBoxGuestAdditions.iso
  Mounting Virtualbox Guest Additions ISO to: /mnt
  mount: /dev/loop0 is write-protected, mounting read-only
  Installing Virtualbox Guest Additions 6.0.14 - guest version is 6.0.14
  Verifying archive integrity... All good.
  Uncompressing VirtualBox 6.0.14 Guest Additions for Linux........
  VirtualBox Guest Additions installer
  Removing installed version 6.0.14 of VirtualBox Guest Additions...
  Copying additional installer modules ...
  Installing additional modules ...
  VirtualBox Guest Additions: Starting.
  VirtualBox Guest Additions: Building the VirtualBox Guest Additions kernel
  modules.  This may take a while.
  VirtualBox Guest Additions: To build modules for other installed kernels, run
  VirtualBox Guest Additions:   /sbin/rcvboxadd quicksetup &lt;version&gt;
  VirtualBox Guest Additions: or
  VirtualBox Guest Additions:   /sbin/rcvboxadd quicksetup all
  VirtualBox Guest Additions: Building the modules for kernel
  3.10.0-1062.7.1.el7.x86_64.
  VirtualBox Guest Additions: Running kernel modules will not be replaced until
  the system is restarted
  An error occurred during installation of VirtualBox Guest Additions 6.0.14. Some functionality may not work as intended.
  In most cases it is OK that the "Window System drivers" installation failed.
  Redirecting to /bin/systemctl start vboxadd.service
  Redirecting to /bin/systemctl start vboxadd-service.service
  Unmounting Virtualbox Guest Additions ISO from: /mnt
  ==&gt; default: Checking for guest additions in VM...
  ==&gt; default: [vagrant-hostsupdater] Checking for host entries
  ==&gt; default: Mounting shared folders...
      default: /vagrant =&gt; C:/Users/Paul M/Projects/centos-docker
  ==&gt; default: Machine already provisioned. Run `vagrant provision` or use the `--provision`
  ==&gt; default: flag to force provisioning. Provisioners marked to run always will still run.
  PS C:\Users\Paul M\projects\centos-docker&gt;
  </code></pre>