Fix --skip in Travis with default Makefile.
Fix --skip in Travis with default Makefile.

am11/libsass,saper/libsass,saper/libsass,admire93/libsass-python,rodneyrehm/libsass,mtwebster/mint-libsass,khchanel/libsass,saper/libsass,panicinc/libsass,moovweb/libsass,rodneyrehm/libsass,webdev1001/libsass,moovweb/libsass,rodneyrehm/libsass,mtwebster/mint-libsass,saper/libsass,webdev1001/libsass,FishingCactus/libsass,saper/libsass,TBAPI-0KA/NSass,admire93/libsass-python,errorx666/libsass,panicinc/libsass,moovweb/libsass,FishingCactus/libsass,webdev1001/libsass,panicinc/libsass,khchanel/libsass,mtwebster/mint-libsass,technoAri/libsass,panicinc/libsass,FishingCactus/libsass,mtwebster/mint-libsass,khchanel/libsass,rodneyrehm/libsass,am11/libsass,webdev1001/libsass,technoAri/libsass,mikebarkas/libsass,TBAPI-0KA/NSass,am11/libsass,mikebarkas/libsass,TBAPI-0KA/NSass,am11/libsass,FishingCactus/libsass,technoAri/libsass,khchanel/libsass,mikebarkas/libsass,rodneyrehm/libsass,dahlia/libsass-python,mikebarkas/libsass,panicinc/libsass,errorx666/libsass,technoAri/libsass,dahlia/libsass-python,errorx666/libsass,mtwebster/mint-libsass,moovweb/libsass,webdev1001/libsass,khchanel/libsass,errorx666/libsass,TBAPI-0KA/NSass,FishingCactus/libsass,TBAPI-0KA/NSass,technoAri/libsass,am11/libsass,mikebarkas/libsass,TBAPI-0KA/NSass