driver: Remove calls to in favor of Vagrant's built in graceful halt

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 IMPROVEMENTS:
 
+  - Remove `lxc-shutdown` usage in favor of Vagrant's built in graceful halt
   - Add fallback mechanism for platforms without `lxc-attach` support [[GH-294]]
 
 [GH-294]: https://github.com/fgrehm/vagrant-lxc/pull/294

lib/vagrant-lxc/driver.rb

@@ -104,10 +104,6 @@ module Vagrant
 
       def forced_halt
         @logger.info('Shutting down container...')
-        # TODO: Remove `lxc-shutdown` usage, graceful halt is enough
-        @cli.transition_to(:stopped) { |c| c.shutdown }
-      # REFACTOR: Do not use exception to control the flow
-      rescue CLI::TargetStateNotReached, CLI::ShutdownNotSupported
         @cli.transition_to(:stopped) { |c| c.stop }
       end
 

lib/vagrant-lxc/driver/cli.rb

@@ -10,7 +10,6 @@ module Vagrant
         attr_accessor :name
 
         class TransitionBlockNotProvided < RuntimeError; end
-        class ShutdownNotSupported < RuntimeError; end
         class TargetStateNotReached < RuntimeError
           def initialize(target_state, state)
             msg = "Target state '#{target_state}' not reached, currently on '#{state}'"
@@ -81,15 +80,6 @@ module Vagrant
           run :stop, '--name', @name
         end
 
-        def shutdown
-          if system('which lxc-shutdown > /dev/null')
-            run :shutdown, '--name', @name
-          else
-            # REFACTOR: Do not use exception to control the flow
-            raise ShutdownNotSupported
-          end
-        end
-
         def attach(*cmd)
           cmd = ['--'] + cmd