update phpunit for Travis
update phpunit for Travis

hopefully this fixes the recent failures

gushphp/gush,sstok/gush,gushphp/gush,cordoval/gush,pierredup/gush,webflo/gush,sstok/gush,sstok/gush,gushphp/gush,cordoval/gush,webflo/gush,pierredup/gush,cordoval/gush,gushphp/gush,pierredup/gush,webflo/gush