use 1.7 target when running on 1.8 for now
use 1.7 target when running on 1.8 for now

the embedded objectweb asm lib that JRuby has doesn't have a 1.8 target yet, so running on 1.8 fails

KeenS/mirah,felixvf/mirah,mirah/mirah,felixvf/mirah,uujava/mirah,mirah/mirah,felixvf/mirah,KeenS/mirah,uujava/mirah,felixvf/mirah,KeenS/mirah,mirah/mirah,KeenS/mirah,uujava/mirah,uujava/mirah,uujava/mirah,mirah/mirah