Don't wait for threads to start Cockpit interface

We don't need to wait for threads to start the Firefox browser. The JS
code will wait for services to show up anyway so let's start firefox as
soon as we can without waiting.

Related: rhbz#2236438

pyanaconda/ui/webui/__init__.py

@@ -22,7 +22,6 @@
 from pyanaconda.core.constants import QUIT_MESSAGE, PAYLOAD_TYPE_DNF, WEBUI_VIEWER_PID_FILE
 from pyanaconda.core.util import startProgram
 from pyanaconda.anaconda_loggers import get_module_logger
-from pyanaconda.core.threads import thread_manager
 from pyanaconda.core.configuration.anaconda import conf
 from pyanaconda.core.process_watchers import PidWatcher
 from pyanaconda.core.glib import create_main_loop
@@ -75,11 +74,6 @@ def setup(self, data):
 
         This method must be provided by all subclasses.
         """
-        # Finish all initialization jobs.
-        # FIXME: Control the initialization via DBus.
-        self._print_message("Waiting for all threads to finish...")
-        thread_manager.wait_all()
-
         # Verify the payload type.
         # FIXME: This is a temporary check.
         if self.payload.type == PAYLOAD_TYPE_DNF: