Merge pull request #4619 from dlundgren/master

Don't update the NFS exports file [GH-4148]

plugins/synced_folders/nfs/synced_folder.rb

@@ -69,6 +69,8 @@ module VagrantPlugins
           end
         end
 
+        # Update the exports when there are actually exports [GH-4148]
+        if !export_folders.empty?
           # Export the folders. We do this with a class-wide lock because
           # NFS exporting often requires sudo privilege and we don't want
           # overlapping input requests. [GH-2680]
@@ -85,6 +87,7 @@ module VagrantPlugins
               retry
             end
           end
+        end
 
         # Mount
         machine.ui.info I18n.t("vagrant.actions.vm.nfs.mounting")