Ubuntu will emit a `vagrant-mounted` event. [GH-576]

There will be a MOUNTPOINT variable available with this event that
will point to the shared folder that has been mounted.

CHANGELOG.md

@@ -45,6 +45,8 @@
     folders. [GH-551]
   - Options passed after a `--` to `vagrant ssh` are now passed directly to
     `ssh`. [GH-554]
+  - Ubuntu guests will now emit a `vagrant-mounted` upstart event after shared
+    folders are mounted.
   - Removed Thor as a dependency for the command line interfaces. This resulted
     in general speed increases across all command line commands.
   - Linux uses `shutdown -h` instead of `halt` to hopefully more consistently

lib/vagrant/guest/ubuntu.rb

@@ -3,6 +3,14 @@ require 'vagrant/guest/debian'
 module Vagrant
   module Guest
     class Ubuntu < Debian
+      def mount_shared_folder(name, guestpath, options)
+        # Mount it like normal
+        super
+
+        # Emit an upstart event if upstart is available
+        @vm.channel.sudo("[ -x /sbin/initctl ] && /sbin/initctl emit vagrant-mounted MOUNTPOINT=#{guestpath}")
+      end
+
       def change_host_name(name)
         if !vm.channel.test("sudo hostname | grep '#{name}'")
           vm.channel.sudo("sed -i 's/.*$/#{name}/' /etc/hostname")