fix(coreos-base/oem-vagrant): Move user config handling out of ruby code

There's no reason for handling vagrantfile-user-data in the Vagrant
plugin, move it to the OEM cloud-config.yml along side the user-data
handler. Use the generic user-config@ unit as well.

sdk_container/src/third_party/coreos-overlay/coreos-base/oem-vagrant/files/box/override-plugin.rb

@@ -14,23 +14,6 @@ BASE_CLOUD_CONFIG = <<EOF
 
 coreos:
     units:
-      - name: coreos-cloudinit-vagrant-user.path
-        command: start
-        runtime: no
-        content: |
-          [Path]
-          PathExists=/var/lib/coreos-vagrant/vagrantfile-user-data
-      - name: coreos-cloudinit-vagrant-user.service
-        runtime: no
-        content: |
-          [Unit]
-          ConditionFileNotEmpty=/var/lib/coreos-vagrant/vagrantfile-user-data
-
-          [Service]
-          Type=oneshot
-          EnvironmentFile=/etc/environment
-          ExecStart=/usr/bin/coreos-cloudinit --from-file /var/lib/coreos-vagrant/vagrantfile-user-data
-          RemainAfterExit=yes
 EOF
 
 NETWORK_UNIT = <<EOF

sdk_container/src/third_party/coreos-overlay/coreos-base/oem-vagrant/files/cloud-config.yml

@@ -8,6 +8,13 @@ coreos:
           [Path]
           PathExists=/var/lib/coreos-vagrant/user-data
           Unit=system-cloudinit@var-lib-coreos\x2dvagrant-user\x2ddata.service
+      - name: coreos-cloudinit-vagrant-user.path
+        command: start
+        runtime: no
+        content: |
+          [Path]
+          PathExists=/var/lib/coreos-vagrant/vagrantfile-user-data
+          Unit=user-cloudinit@var-lib-coreos\x2dvagrant-vagrantfile\x2duser\x2ddata.service
     oem:
       id: vagrant
       name: Vagrant