Ignore SIGINT in D-Bus launcher and x11 too

When we do install, especially use TUI to install, we some time have take
a mistake to put "CTRL+C", then there will be stop with traceback. And we
know the main process have shielded SIGINT, so we to shield subprocesses also.

pyanaconda/core/startup/dbus_launcher.py

@@ -24,6 +24,7 @@
 # Author(s):  Jiri Konecny <jkonecny@redhat.com>
 #
 import os
+import signal
 from subprocess import TimeoutExpired
 
 from pyanaconda.core.configuration.anaconda import conf
@@ -109,9 +110,14 @@ def _start_dbus_session(self):
             "--syslog",
             "--config-file={}".format(ANACONDA_BUS_CONF_FILE)
         ]
+
+        def dbus_preexec():
+            # to set dbus subprocess SIGINT handler
+            signal.signal(signal.SIGINT, signal.SIG_IGN)
 
         self._log_file = open('/tmp/dbus.log', 'a')
-        self._dbus_daemon_process = startProgram(command, stderr=self._log_file, reset_lang=False)
+        self._dbus_daemon_process = startProgram(command, stderr=self._log_file, reset_lang=False,
+                                                 preexec_fn=dbus_preexec)
 
         if self._dbus_daemon_process.poll() is not None:
             raise RuntimeError("DBus wasn't properly started!")

pyanaconda/display.py

@@ -24,6 +24,7 @@
 import time
 import textwrap
 import pkgutil
+import signal
 
 from pyanaconda.core.configuration.anaconda import conf
 from pyanaconda.core.process_watchers import WatchProcesses
@@ -192,8 +193,13 @@ def do_startup_x11_actions():
     else:
         xdg_data_dirs = datadir + '/window-manager:/usr/share'
 
+    def x11_preexec():
+        # to set GUI subprocess SIGINT handler
+        signal.signal(signal.SIGINT, signal.SIG_IGN)
+
     childproc = util.startProgram(["gnome-kiosk", "--display", ":1", "--sm-disable", "--x11"],
-                                  env_add={'XDG_DATA_DIRS': xdg_data_dirs})
+                                  env_add={'XDG_DATA_DIRS': xdg_data_dirs},
+                                  preexec_fn=x11_preexec)
     WatchProcesses.watch_process(childproc, "gnome-kiosk")