core: if can't communicate, force halt right away

lib/vagrant/action/builtin/graceful_halt.rb

@@ -44,13 +44,10 @@ module Vagrant
           # Only attempt to perform graceful shutdown under certain cases
           # checked above.
           if graceful
-            env[:ui].info I18n.t("vagrant.actions.vm.halt.graceful")
+            env[:ui].output(I18n.t("vagrant.actions.vm.halt.graceful"))
 
             begin
               env[:machine].guest.capability(:halt)
-            rescue Errors::MachineGuestNotReady
-              @logger.info("Machine guest not ready while attempting to halt. Ignoring.")
-            end
 
               @logger.debug("Waiting for target graceful halt state: #{@target_state}")
               begin
@@ -62,6 +59,9 @@ module Vagrant
               rescue Timeout::Error
                 # Don't worry about it, we catch the case later.
               end
+            rescue Errors::MachineGuestNotReady
+              env[:ui].detail(I18n.t("vagrant.actions.vm.halt.guest_not_ready"))
+            end
 
             # The result of this matters on whether we reached our
             # proper target state or not.

templates/locales/en.yml

@@ -1312,6 +1312,11 @@ en:
             Forcing shutdown of VM...
           graceful: |-
             Attempting graceful shutdown of VM...
+          guest_not_ready: |-
+            Guest communication could not be established! This is usually because
+            SSH is not running, the authentication information was changed,
+            or some other networking issue. Vagrant will force halt, if
+            capable.
         hostname:
           setting: "Setting hostname..."
         import: