lua-factory: Fix warning in Apple trailers source
lua-factory: Fix warning in Apple trailers source

We should make the filesize a number, not pass it
down as a string.

[lua-library] grl-lua-library.c:399: 'string' is not compatible for 'size'

https://bugzilla.gnome.org/show_bug.cgi?id=788557

GNOME/grilo-plugins,MikePetullo/grilo-plugins,grilofw/grilo-plugins,jasuarez/grilo-plugins,MikePetullo/grilo-plugins,jasuarez/grilo-plugins,MikePetullo/grilo-plugins,GNOME/grilo-plugins,grilofw/grilo-plugins