Revert "also test against openjdk8"
Revert "also test against openjdk8"

This reverts commit 5c1faa3ad4c52133f12373dc812ac803112a3655.
openjdk8 does not exist on travis (yet?)

ghiringh/Wegas,ghiringh/Wegas,Heigvd/Wegas,Heigvd/Wegas,Heigvd/Wegas,ghiringh/Wegas,Heigvd/Wegas,Heigvd/Wegas