Don't filter out "missing" files in the glob stage.
Don't filter out "missing" files in the glob stage.

Commit bd6b9d8 dramatically changed the way that files are loaded, and had the
side-effect of filtering out any files which were sourced by finders outside of
the main `STATICFILES_DIRS`.

In the case I'm trying to address, we have an extension framework (in Review
Board and Djblets) which can load static media from third-party packages which
are activated at runtime. This media is loaded by instantiating
`StylesheetNode` and `JavascriptNode` from `pipeline.templatetags` in
combination with a special finder. Because django-pipeline no longer uses
finders before the compile stage, calling `storage.exists` (via
`Package.sources` -> `glob`) silently filters these out.

Inside `glob`, I agree that it's useful to test existence when trying to expand
`*` or `?`, but when the path is just a normal filename, it should be safe to
assume that the user knows what they're doing. This causes the paths to be
emitted into the rendered template whether or not `staticfiles_storage` claims
they exist, and anything which the configured staticfiles finders can't locate
will surface as a 404 rather than being silently eaten.

jazzband/django-pipeline,beedesk/django-pipeline,theatlantic/django-pipeline,beedesk/django-pipeline,kronion/django-pipeline,beedesk/django-pipeline,kronion/django-pipeline,jazzband/django-pipeline,theatlantic/django-pipeline,lexqt/django-pipeline,cyberdelia/django-pipeline,d9pouces/django-pipeline,lexqt/django-pipeline,theatlantic/django-pipeline,chipx86/django-pipeline,chipx86/django-pipeline,jazzband/django-pipeline,sideffect0/django-pipeline,lexqt/django-pipeline,sideffect0/django-pipeline,d9pouces/django-pipeline,kronion/django-pipeline,cyberdelia/django-pipeline,d9pouces/django-pipeline,chipx86/django-pipeline,cyberdelia/django-pipeline,sideffect0/django-pipeline