macosx: fix bug in disk open panel regarding selected folders
macosx: fix bug in disk open panel regarding selected folders

Previously, the open panel always converted the mrl to an (not available)
mount point when you want to setup a playback without menus

jomanmuk/vlc-2.2,xkfz007/vlc,jomanmuk/vlc-2.1,shyamalschandra/vlc,shyamalschandra/vlc,jomanmuk/vlc-2.2,krichter722/vlc,jomanmuk/vlc-2.2,shyamalschandra/vlc,vlc-mirror/vlc,shyamalschandra/vlc,jomanmuk/vlc-2.2,vlc-mirror/vlc,vlc-mirror/vlc,krichter722/vlc,xkfz007/vlc,jomanmuk/vlc-2.1,jomanmuk/vlc-2.1,xkfz007/vlc,krichter722/vlc,shyamalschandra/vlc,jomanmuk/vlc-2.1,vlc-mirror/vlc-2.1,vlc-mirror/vlc-2.1,vlc-mirror/vlc,xkfz007/vlc,krichter722/vlc,jomanmuk/vlc-2.1,vlc-mirror/vlc,vlc-mirror/vlc-2.1,krichter722/vlc,vlc-mirror/vlc,vlc-mirror/vlc-2.1,vlc-mirror/vlc-2.1,krichter722/vlc,shyamalschandra/vlc,xkfz007/vlc,jomanmuk/vlc-2.1,xkfz007/vlc,vlc-mirror/vlc-2.1,vlc-mirror/vlc,jomanmuk/vlc-2.1,vlc-mirror/vlc-2.1,shyamalschandra/vlc,krichter722/vlc,jomanmuk/vlc-2.2,xkfz007/vlc,jomanmuk/vlc-2.2,jomanmuk/vlc-2.2