_location_process_location should use field defaults

Problem/Motivation

I don't really know if this is a bug or not, but shouldn't _location_process_location() use the $fdefaults to check if it has a location?

I have a module which uses a location element in the edit form for a Page Manager Panel pane. Since this is not a saved location, _location_process_location() creates a new empty location, which is used to create the markup for the "current location" fieldset. However it should (at least in my case) look at the form element defaults instead.

Proposed resolution

Use the $fdefaults instead of $defaults.