smb: Report proper error on do_query_fs_info()
smb: Report proper error on do_query_fs_info()

We always reported success despite storing the smb call result.

https://bugzilla.gnome.org/show_bug.cgi?id=687778

halfline/gvfs,gicmo/gvfs,halfline/gvfs,xkahn/gvfs-cmis,halfline/gvfs,xkahn/gvfs-cmis,xkahn/gvfs-cmis,xkahn/gvfs-cmis,gicmo/gvfs,gicmo/gvfs,gicmo/gvfs