jp (shell): use of subprocess instead of running commands in the same process:

when a command is calling host.quit() in a D-Bus callback, GLib mainloop is exiting and quit the whole process without (apparently?) any way to block it. Couldn't find a good way to avoid that, so subprocess are now used as a workaround, instead of launching commands in the same process. When we'll get rid of python-dbus, there may be an other way.

Execuring external commands is now possible through the shell/! command.

frontends/src/jp/base.py

@@ -165,9 +165,6 @@ class Jp(object):
 
         self.bridge = bridge_module.Bridge()
         self.bridge.bridgeConnect(callback=self._bridgeCb, errback=self._bridgeEb)
-        # _no_exit is used in shell mode because SystemExit can't
-        # catched in some cases
-        self._no_exit = False
 
     def _bridgeCb(self):
         self.parser = argparse.ArgumentParser(formatter_class=argparse.RawDescriptionHelpFormatter,
@@ -445,8 +442,7 @@ class Jp(object):
                 callback(*args, **kwargs)
 
         self.stop_loop()
-        if not self._no_exit:
-            sys.exit(errcode)
+        sys.exit(errcode)
 
     def check_jids(self, jids):
         """Check jids validity, transform roster name to corresponding jids