use local phpunit command in travis
use local phpunit command in travis

Signed-off-by: Eric Villard <34c6fceca75e456f25e7e99531e2425c6c1de443@eviweb.fr>

eviweb/fuelphp-phpcs,nishaya/fuelphp-phpcs,eviweb/fuelphp-phpcs,nishaya/fuelphp-phpcs