travis: use released version
travis: use released version

yoku0825/mroonga,naoa/mroonga,yoku0825/mroonga,mroonga/mroonga,yoku0825/mroonga,naoa/mroonga,mroonga/mroonga,yoku0825/mroonga,naoa/mroonga,yoku0825/mroonga,naoa/mroonga,naoa/mroonga,mroonga/mroonga,mroonga/mroonga,yoku0825/mroonga,naoa/mroonga