fix extract image extracting from proxy producer instead of original producer

Review Request #128937 - Created Sept. 18, 2016 and submitted

The DiveO

When extract frame detects a proxy it tries to use the property "resource" for extracting from the original clip; however, this property points to the proxy clip, but not the original. Instead, the property "kdenlive:originalurl" looks like what originally was intended. Not least the preceeding comment mentions to use the original clip url ... and that strongly points towards the property "kdenlive:originalurl".

Using fresh recent Kdenlive git master.

The DiveO
Review request changed

Status: Closed (submitted)

Change Summary:

Submitted with commit 16d894c61d4d6875b7bed4297a30a410c33bcb28 by Jean-Baptiste Mardelle to branch master.