Revert "Fix hang, don't wait on managers, they just chill"

This reverts commit 5e2a0cd.
It was the right idea, but not quite there yet.

lib/specjour/dispatcher.rb

@@ -16,7 +16,7 @@ def initialize(options = {})
       @managers = []
       @drb_connection_errors = Hash.new(0)
       @rsync_port = options[:rsync_port]
-      @manager_threads = []
+      reset_manager_threads
     end
 
     def start
@@ -25,6 +25,7 @@ def start
       rsync_daemon.start
       dispatch_work
       printer.start if dispatching_tests?
+      wait_on_managers
       exit printer.exit_status
     end
 
@@ -122,6 +123,10 @@ def project_name
       @project_name ||= File.basename(project_path)
     end
 
+    def reset_manager_threads
+      @manager_threads = []
+    end
+
     def resolve_reply(reply)
       DNSSD.resolve!(reply.name, reply.type, reply.domain, flags=0, reply.interface) do |resolved|
         Specjour.logger.debug "Bonjour discovered #{resolved.target}"
@@ -153,6 +158,11 @@ def set_up_manager(manager)
       end
     end
 
+    def wait_on_managers
+      manager_threads.each {|t| t.join; t.exit}
+      reset_manager_threads
+    end
+
     def worker_task
       options[:worker_task] || 'run_tests'
     end