registry: Only scan plugin files that end with an extension
registry: Only scan plugin files that end with an extension

Not file that would for some reason end with 'so' or 'dll', etc...

https://bugzilla.gnome.org/show_bug.cgi?id=779175

StreamUtils/gstreamer,StreamUtils/gstreamer,StreamUtils/gstreamer,StreamUtils/gstreamer,StreamUtils/gstreamer