On an i.MX6, this test can take around 15 minutes under normal
conditions, so any network delays are going to tip it over the edge and
cause test failures due to timeouts.

Double the timeout to 30 minutes to hopefully avoid this.

Bug: https://bugs.apertis.org/show_bug.cgi?id=476


Signed-off-by: Philip Withnall <philip.withnall@collabora.co.uk>
Reviewed-by: Luis Araujo <luis.araujo@collabora.com>
Differential Revision: https://phabricator.apertis.org/D429