Increase ansible gather_timeout to 30secs for config-download
Increase ansible gather_timeout to 30secs for config-download

With ansible 2.6.2 the facts gathering run time seems to be much
longer [1], causing unpredictable failures like [2]

1. https://github.com/ansible/ansible/issues/43884
2. https://logs.rdoproject.org/60/14960/17/check/legacy-rdoinfo-tripleo-master-testing-centos-7-multinode-1ctlr-featureset016/b93ed7f/logs/undercloud/home/zuul/overcloud_deploy.log.txt.gz#_2018-11-08_18_43_14

Change-Id: Ia4aeac06d4c0e237180e4ba60063828b0d1c5350
Closes-Bug: 1806073

openstack/tripleo-common,openstack/tripleo-common