Create the homedir last to avoid symlink issues

If the homedir is on a symlink (say /home -> /var/home) but the homedir
is in /home, then we shouldn't create a directory in /home because
then the symlink creation will fail. Instead we move the homedir
creation to the end, where we will create it in the symlink if needed.

This should fix https://github.com/flatpak/flatpak/issues/493

common/flatpak-run.c

@@ -2657,6 +2657,11 @@ flatpak_run_add_environment_args (GPtrArray      *argv_array,
   /* This actually outputs the args for the hide/expose operations above */
   add_file_args (argv_array, fs_paths);
 
+  /* Ensure we always have a homedir */
+  add_args (argv_array,
+            "--dir", g_get_home_dir (),
+            NULL);
+
   /* Special case subdirectories of the cache, config and data xdg dirs.
    * If these are accessible explicilty, in a read-write fashion, then
    * we bind-mount these in the app-id dir. This allows applications to
@@ -3850,8 +3855,6 @@ flatpak_run_setup_base_argv (GPtrArray      *argv_array,
             "--ro-bind", "/sys/devices", "/sys/devices",
             "--bind-data", passwd_fd_str, "/etc/passwd",
             "--bind-data", group_fd_str, "/etc/group",
-            /* Always create a homedir to start from, although it may be covered later */
-            "--dir", g_get_home_dir (),
             NULL);
 
   if (g_file_test ("/etc/machine-id", G_FILE_TEST_EXISTS))