gio/tests/file: increase an arbitrary timeout
gio/tests/file: increase an arbitrary timeout

On slow ARM machines doing parallel builds, there's no guarantee that
we'll get through this in 5 seconds.

Signed-off-by: Simon McVittie <2b470b34502dbf3ba4bcc04ea7e64f4e0e104f33@collabora.co.uk>
Reviewed-by: Philip Withnall <29c2a2ac2a854b9cf047275aa9de346d096be2e0@endlessm.com>
Bug: https://bugzilla.gnome.org/show_bug.cgi?id=769674

endlessm/glib,johne53/MB3Glib,endlessm/glib,johne53/MB3Glib,endlessm/glib,johne53/MB3Glib,johne53/MB3Glib,endlessm/glib,endlessm/glib,johne53/MB3Glib,johne53/MB3Glib