nautilus-directory.c: Fix a memory leak.

When creating a new file using a template, it's possible for is_added
to be FALSE, so make sure the file is unref'd regardless.

This actually resolves an issue in caja and nemo which is caused by
files created in this manner not being finalized when no longer in use.
I can reproduce the issue with nautilus, but this *does not* fix it,
so I think that there may be an additional leak somewhere else (maybe
not related to template-created files).

To reproduce:
- Create an svg file and save in ~/Templates.
- Right-click, Create document-> svg file, name it whatever.
- Navigate out of the folder.
- Modify the file in a visible manner.
- Re-enter the folder, note that it never finishes loading.

Original report:
https://github.com/linuxmint/nemo/issues/2736
5 jobs for master in 15 minutes and 32 seconds (queued for 1 second)
Status Job ID Name Coverage
  Image
manual #1337076
allowed to fail manual
update image
 
  Test
passed #1337077
flatpak
flatpak devel

00:09:14

passed #1337078
style check

00:01:25

 
  Cross Environment
passed #1337079
fedora rawhide

00:02:12

 
  Deploy
passed #1337080
nightly

00:04:05