Fix opening Desktop entries with Path

Desktop Entry files can specify a working directory for the path.
Instead of prepending that path to the command, we instead change the
current working directory in the executable context so that those
applications can load correctly.

mate_menu/execute.py

@@ -36,7 +36,7 @@ def RemoveArgs(Execline):
 # Actually launch the application
 def Launch(cmd, cwd=None):
 	if cwd:
-		cmd = cwd + ' ' + cmd
+		os.chdir(cwd)
 
 	app_info = Gio.AppInfo.create_from_commandline(cmd,
 						       None,